International Rice Research Newsletter Vol.14 No.4

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Categories of research reported GERMPLASM IMPROVEMENT

genetic resources genetics breeding methods yield potential grain quality and nutritional value disease resistance insect resistance drought tolerance excess water tolerance adverse temperature tolerance adverse soils tolerance integrated germplasm improvement seed technology research techniques data management and computer

modeling

CROP AND RESOURCE MANAGEMENT

soils and soil characterization soil microbiology and biological N

physiology and plant nutrition crop management soil fertility and fertilizer management disease management insect management weed management managing other pests integrated pest management water management farm machinery environmental analysis postharvest technology farming systems research methodology data management and computer

fertilizer

modeling

SOCIOECONOMIC AND ENVIRONMENTAL IMPACT

environment production livelihood

EDUCATION AND COMMUNICATION

training and technology transfer

communication research information storage and retrieval

research

CONTENTS

GERMPLASM IMPROVEMENT

Genetic resources 5 Two species of Oryza officinalis complex present in Sri Lanka

5 Preliminary studies on the relationships between Lu Dao and Yunnan

6 Dominance relationship and nature of genetic variances for yield and

6 Genetic divergence in upland rice 7 Pollen development and hybridization between indica varieties of rice 8 Cell division in indica rice varieties

Genetics

land varieties of Oryza sativa L.

its components in rice

Breeding methods 8 Transfer eui gene to WA-MS line Zhen-Shan 97A (Oryza sativa ssp.

9 Performance of hybrid rice in Indonesia 9 Stubble planting—promising vegetative propagation method for

indica) and eliminating its panicle enclosure

hybrid rice 10 Performance of F 1 hybrids in Jammu and Kashmir

Yield potential 11 Varietal response to typhoon injury in Nellore, Andhra Pradesh, India 11 Time of panicle initiation and flowering in some rice varieties 11 Path analysis of yield components and selected agronomic traits of

12 Relationship between grain yield and light transmission in rice 12 Relationship of rainfall distribution patterns to rice productivity 13 Selecting for photoperiod sensitivity in pedigree nurseries 14 Relationship between grain yield and flag leaf angle in rice

upland rice breeding lines

Grain quality and nutritional value 14 Grain quality of some promising rice genotypes 15 Modified single grain analysis for gel consistency

15 Relationship between tungro (RTV) and sheath rot (ShR) in three rice

15 Reaction of some promising rice cultivars to grassy stunt virus (GSV) 16 Virulence of six isolates of Xanthomonas campestris pv. oryzae on rice 16 Field resistance to false smut (FS) and narrow brown leaf spot (NBLS)

17 Sources of resistance to rice yellow dwarf and its vector 17 Technique to preserve conidia of rice blast (Bl) fungus 18 Methods for evaluating resistance to Pyricularia oryzae in rice

19 Effect of rice gall midge (GM) resistance on parasitic behavior of

Disease resistance

cultivars

in eastern Uttar Pradesh

Insect resistance

Platygaster oryzae Cameron Drought resistance

20 Screening advanced breeding lines and germplasm for drought resistance under upland conditions

Excess water tolerance 20 Promising breeding lines for submergence-prone and medium-deep

rainfed lowland conditions Adverse temperature tolerance

21 Screening rice seedlings for cold tolerance Adverse soils tolerance

21 Effect of increased salinity on rice genotypes

22 Rajshree, a new rice variety for rainfed lowlands in Bihar, India 22 Evaluation of upland rice lines at Morogoro, Tanzania 23 Yield potential of IR7167-33-2-3 and Tainan V at Ndop Plain,

24 ASD 17, a short-duration red rice variety for tail end irrigation areas of

24 Performance of some improved rice varieties under irrigated and

Integrated germplasm improvement

Northwest Cameroon

Tambiraparani Delta and Kanyakumari District, Tamil Nadu

rainfed lowland conditions at Parwanipur, Nepal

25 NAU2159, a high-yielding glutinous rice for East China 26 Performance of some promising rice cultivars for tidal marshy swamps

26 Zhongyu 87-1, promising line developed through shuttle breeding

27 Simulation of yield potential in rice cultivars

27 Screening rice varieties for grain dormancy

of Andamans

Data management and computer modeling

Seed technology

CROP AND RESOURCE MANAGEMENT Crop management

28 Yields of broadcast and transplanted Oryza glaberrima floating rice 29 Varietal differences in milled quality of rice harvested at different

maturities 29 Effect on yield of cutting deepwater rice for herbage 30 Improving rice yield using hydrocortisone spray

Soil fertility and fertilizer management 30 Using a chlorophyll meter to predict need for topdressed nitrogen 31 Economy in combining fertilizer N with green manure in lowland rice 31 Effect of deep-placed urea supergranules (USG) with limited green

32 Integrated nutrient management in irrigated rice 32 Effect on rice yield of N applied during reproductive phase 33 Effect of single superphosphate and granular superphosphate fertilizer

33 Performance of Sesbania rostrata in acid soils

manure on transplanted rice yield

on rice yield

Disease management 34 Conidia release and dispersal pattern of Pyricularia oryzae under

34 Yield loss due to rice blast (Bl) disease at different crop stages 35 Estimating yield loss to rice blast (Bl) disease 35 Reaction of four rice cultivars to grassy stunt virus (GSV) strain 2

35 Control of blast (Bl) in main field and nursery with some new

cloudy or rainy conditions

under natural conditions

fungicides Insect management

36 Effect of lunar phase on attraction of rice pests to black light trap 36 Severe outbreak of rice gall midge (GM) in the savannah zone, Nigeria 37 Response of rice pests to mercury vapor light and black light traps 37 Sex and reproductive status of rice stem borers and leafhoppers

38 Pentatomid bugs reduce rice grain quality in farmers’ fields in Orissa

38 Influence of herbicide carrier and application method on weed control 38 Effect of herbicide mixtures in transplanted rice 39 Effect of time and method of application of herbicides on yield and

attracted to black light trap

Weed management

yield components of rainfed lowland rice Farm machinery

40 Effect of soil moisture content on power requirements

40 Uric acid content of stored rice Postharvest technology

Farming systems 41 Establishing wheat with minimal tillage and irrigation after rice 41 A rice-based intercropping sequence for Vindhyan red loam soils of

42 Effect of green manure and inorganic N in rice - rice - pulse - cropping

43 Residual effect of fertilizer applied to rice in rice - fallow - cotton 43 Effect of source and level of nitrogen on yield of rice and succeeding

44 Residual effect on succeeding winter rice of urea applied to summer

eastern Uttar Pradesh

system

lentil crop

rice

SOCIOECONOMIC AND ENVIRONMENTAL IMPACT Livelihood

44 Energy use in rice - wheat cropping system

ANNOUNCEMENTS 45 Alley Farming Network for Tropical Africa 45 New IRRI publications 45 IPM newsletter discontinued

ERRATUM

GERMPLASM IMPROVEMENT Genetic resources

Two species of Oryza officinalis complex present in Sri Lanka

D. A. Vaughan, International Rice Germplasm Center, IRRI

We compared Oryza eichingeri (formerly called Oryza collina in its Sri Lankan form) with collections of the Oryza officinalis complex from Sri Lanka in a replicated pot study. Results from this study in combination with field data show two morphologically and ecologically distinct species of the Oryza officinalis complex in Sri Lanka: Oryza eichingeri and a larger rhizomatous species (see table).

The rhizomatous species appears morphologically to be more similar to Oryza officinalis than to other species of the complex. However, O. officinalis usually is found in moist habitats, such as beside streams. Though usually rhizo- matous, it has smaller spikelets, and has more panicle branches of equivalent length from the lower panicle nodes.

The morphological, ecological, and/or geographic distinctiveness of the new taxon from all other species in the genus Oryza warrant its recognition as a new species. The name Oryza rhizomatis Vaughan sp. nov. has been chosen.

A brief Latin description is provided here; full taxonomic treatment will be published elsewhere. Oryza rhizomatis Vaughan sp. nov. Herba perennis rhizomate crasso, ca. 1.2-1.5 m alta inflorescentia paniculata, exserta, erecta, laxa 20-28 cm longa

panicularum rami 5-9. Spicula saepe purpureo-viridis, 5.3-7.7 mm longa, 1.9- 2.4 mm lata. Chromosatum numerus 2n = 2x = 12.

The type collection was made from Anduorwa, Rahuna National Park, Hambantota, Sri Lanka, by S. Balendira, A. S. U. Liyanage, and D. A. Vaughan. The holotype is deposited at the herbarium Kew, UK. IRGC Accs. 103414, 103417, 103427, 105659, and 105660 (type collection) correspond to O. rhizomatis.

Qualitative and quantitative morphological characters of Oryza eichingeri and O. rhizomatis. a

Genetics

Preliminary studies on the relationships between Lu Dao and Yunnan land varieties of Oryza sativa L.

Chen Zengjian and Zhu Lihong, Agronomy Department, Nanjing Agricultural University, Nanjing, China

We studied biological and genetic characters of Lu Dao (an indigenous rice germplasm in Jiangsu Province) and four Yunnan land varieties (Banli 1 [japonica], Haoanwen [japonica], Haopi [indica], and Maxiangu [indica]) and

Mean b

Oryza eichingeri Oryza rhizomatis

Rhizomes Panicle branching Habitat

Culm length (cm) Flag leaf length (mm) Flag leaf width (mm) Flag leaf ligule length (mm) Panicle length (mm) Grain length (mm) Grain width (mm) Awn length (mm)

Absent Compact to semiopen

Partial shade, moist

100.3 (9.4)** 135.2 (19.6)**

12.3 (1.7)** 0.3 (0.2)**

160.8 (28.1)** 5.5 (0.3)* 1.8 (0.16)**

18.2 (3.9)**

Present Wide and spreading

Open to partial shade, seasonally dry 135.4 (13.5)** 238.3 (36.3)**

15.3 (1.5)** 1.7 (0.5)**

237.0 (18.2)** 6.0 (0.7)* 2.2 (0.15)** 7.7 (4.0)**

a O. eichingeri 3 accessions; O. rhizomatis, 5 accessions. Each accession was replicated 3 times, and the mean measurement for each quantitative trait was used in the analysis. b Values in parentheses are standard deviation. **, * = significantly different at 1 and 5% levels, LSD test.

Chromosomal behavior of Lu Dao and its hybrids at metaphase I and anaphase I. 1986-87, Nanjing, China.

Parents and Metaphase I and anaphase I

hybrids Cells Normal 10+1IV Univalents a Laggards Fragments Others b

observed (%) (%) (%) (%) (%) (no.)

Lu Dao Banli 1 Haoanwen Haopi Maxiangu Banli 1/Lu Dao Haoanwen/Lu Dao Haopi/Lu Dao Maxiangu/Lu Dao Lu Dao/Banli 1 Lu Dao/Haoanwen Lu Dao/Haopi Lu Dao/Maxiangu

233 166 212 244 150 278 480 194 338 278 323 3 24 – c

97.31 98.19 98.11 98.36 98.00 92.81 92.91 90.21 89.05 93.17 94.32 91.36

–

1.35 0.60 0.00 0.00 0.00 2.51 2.29 1.55 1.47 1.80 1.72 1.54

–

0.90 0.45 0.00 0.00 0.60 0.00 0.60 0.00 0.47 0.47 0.00 0.94 0.00 0.41 0.82 0.41 1.33 0.47 0.00 0.00 1.80 1.08 0.72 1.44 0.42 1.46 1.46 2.08 2.57 1.03 3.61 2.66

1.03 0.89 3.25 2.66

0.72 1.08 2.52 0.72 0.43 1.29 1.29 0.86 1.85 1.54 1.54 2.16

– – – –

a 1-4 univalents per cell. b Including 8 II+2IV, early, late and unequal orientations of division and some multivalents at metaphase I and anaphase I. c No results because of late heading,

IRRN 14:4 (August 1989) 5

their hybrids 1984-87. Morphological traits of Lu Dao are more similar to the japonica land varieties.

Seed set of the hybrids of Lu Dao and the japonicas was higher than that of Lu Dao and the indicas. Lu Dao’s easy shedding and long blackish awns are dominant in F 1 progeny. The F 1 plants from Lu Dao and the japonicas showed higher pollen fertility when Lu Dao was used as female parent.

Esterase analysis of embryos indicated that the esterase isozyme bands of Lu

Dao were similar to those of the two japonica varieties. One esterase band of Lu Dao, absent in the indica varieties, appeared in all F 1 hybrids tested.

Cytogenetic studies showed that chromosomal aberrations such as 10 II + 1IV (1.47-2.51%), univalents (0.42- 2.66%, range 1-4 per cell), laggards and straggling chromosomes (0.89-1.54%), bridges and fragments of chromosomes (0.72-3.61%), and some multivalents were common at metaphase I and

Dominance relationship and nature of genetic variances for yield and its components in rice

T. Ram, J. Singh, and R. M. Singh, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India

We crossed 10 divergent rice cultivars (Mahsuri, Dhaneswar, Pawanpeer, Adamchini, TAU 18, Kanakjeera, IR50, IR52, IET7552, IET4140) in all possible combinations (excluding reciprocal) in 1982. Parents, F 1 s, and F 2 s were raised in a compact family randomized block design with three replications.

Plot size for parents and F 1 was one row; for F 2 , six rows of 20 plants each at 20- × 15-cm spacing. Data were collected on days to panicle emergence, plant height, panicle length, effective tillers/ plant, grains/ panicle, chaff seeds/panicle, 100-grain weight, and grain yield/plant.

Means for 15 plants of parents and F 1 and 50 plants of F 2 per replication were subjected to graphical analysis, component analysis, and combining ability analysis of diallel crosses (see table).

Mean dominance degrees estimated through graphical, genetic component, and combining ability analyses differ in

Dominance relationship and nature of genetic variance for yield and yield components.

Degree of dominance

Character Generation Graphical analysis Component analysis Combining (H 1 /D) 1/2 ability

analysis

Days to panicle F 1 Overdominance Overdominance Additive emergence F 2 Partial dominance Complete dominance Additive

Plant height F 1 Partial dominance Partial dominance Additive

Panicle length F 1 Partial dominance Overdominance Nonadditive

Effective tillers/plant F 1 Partial dominance Overdominance Nonadditive

Grains/panicle F 1 Partial dominance Complete dominance Additive

Chaff seeds/panicle F 1 Partial dominance Overdominance Nonadditive

100-grain weight F 1 Partial dominance Partial dominance Additive

Grain yield/plant F 1 Partial dominance Overdominance Nonadditive

F 2 Partial dominance Partial dominance Additive

F 2 Partial dominance Overdominance Nonadditive

F 2 Partial dominance Overdominance Nonadditive

F 2 Complete dominance Complete dominance Additive

F 2 Complete dominance Overdominance Nonadditive

F 2 Partial dominance Partial dominance Additive

F 2 Complete dominance Overdominance Nonadditive

anaphase I in F 1 PMCs (see table). Aberrant chromosomal pairing in the F 1 of Lu Dao and the japonicas appeared to be somewhat lower than in Lu Dao and the indicas. This might indicate more chromosomal structural differences between Lu Dao and the indica varieties.

This analysis suggests that Lu Dao is an intermediate type of rice germplasm, between O. sativa L. ssp. Keng Ting and O. rufipogon Griff.

some characters. Combining ability analysis is the most reliable; results of graphical and component analyses may be seriously affected by correlated gene distribution and/ or presence of epistasis.

Genetic divergence in upland rice

C. R. Anandakumar and M. Subramanian, Agricultural Botany Department, Agricultural College and Research Institute, Mudurai, Tamil Nadu, India

We evaluated 23 drought-resistant cultures from Kerala and Tamil Nadu, India, and IRRI during 1987 wet season for their genetic diversity, using Mahalanobis D 2 analysis.

The varieties were sown in a randomized block design with three replications. At harvest, 15 plants were selected at random from each plot to measure plant height, productive tillers, boot leaf length and breadth, and yield.

Using Tochers’ clustering technique, the genotypes were grouped into six clusters (Table 1). Seven of eight genotypes in cluster I (from IRRI) showed much less variability in their genetic architecture. Cluster III includes types from different geographical regions.

The clustering pattern failed to indicate any relationship between geographic divergence and genetic variability. The genotypes from Tamil Nadu fell into different clusters. The

6 IRRN 14:4 (August 1989)

(2 s 2 g/ s 2 s)

Table 1. Composition of D 2 clusters showing genetic diversity.

Cluster Genotype

I Brown gora (IRRI), BR319-1 (IRRI), OS4 (IRRI), IR12979-24 (IRRI), C22 (IRRI), UPLRi-7 (IRRI), Kala- keri (IRRI), PM1128 (Paramakudi)

(IRRI), N22 (IRRI), Charupuncha (Kerala), PMKl (Paramakudi), Arurakhari (Kerala), PM1381 (Para- makudi

III Azucena (IRRI), Kattanur (Ramnad), Norungan (Ramnad), MDU1 (Madurai)

II 20A (IRRI), OS6 (IRRI), UPLRi-5

IV E45 (IRRI) V IR9575 Sel (IRRI)

VI Moongil Samba (Kerala)

Table 2. Intercluster and intracluster genetic distances.

Clus- I II III IV V VI ter

1 90.52 37.92 65.21 37.68 47.70 165.67 II 92.61 44.38 43.24 39.98 122.32

III 47.38 79.12 38.96 65.50 IV – 85.84 190.89

V – 97.31 VI –

wide genetic variability of genotypes of the same origin might be due to varied phenological conditions.

distance, clusters I, II, IV, and VI were highly divergent (Table 2).

particularly E45, IR9575 sel, and Moongil Samba, in breeding programs could result in high heterosis for qualitative and quantitative characters.

On the basis of intercluster D 2

Use of the genotypes in these clusters,

Pollen development and hybridization between indica varieties of rice

M. Selvanathan and V. K. Khanna, Plant Breeding Department, Pantnagar, India

We crossed four indica rices—IR36, Pant Dhan 4, Rasi, and IET7301—in all possible combinations. Pistils hand pollinated with pollen from dehiscing

Pollen germination and pollen tube growth 60 min after pollination and seed set in crosses of differ- ent rice varieties. a Pantnagu, India.

Pollen Pollen tube Seed Cross germination growth set

(%) (µ) (%)

IR36/IR36 61.00 (4) 602.0 (2) Pant Dhan 4/Pant Dhan 4 72.00 (2) 532.0 (7) Rasi/Rasi 85.00 (1) 591.2 (3) IET7301/IET7301 70.00 (3) 502.0 (9) IR36/Pant Dhan 4 55.50 (6) 546.4 (5) Pant Dhan 4/IR36 19.00 (14) 505.0 (8) IR36/Rasi 25.00 (13) 556.4 (4) Rasi/IR36 51.00 (8) 405.0 (13) IR36/IET7301 37.00 (11b) 542.0 (6) IET7301/IR36 37.00 (11a) 430.0 (12) Pant Dhan 4/Rasi 53.00 (7) 495.0 (10) Rasi/Pant Dhan 4 37.00 (11c) 362.0 (15) Pant Dhan 4/IET7301 34.00 (12) 398.0 (14) IET7301/Pant Dhan 4 46.90 (9) 996.0 (1) Rasi/IET7301 60.00 (5) 493.0 (11) IET7301/Rasi 44.40 (10) 320.0 (16)

a Numbers in parentheses = descending order of values for each character.

anthers of male parents were collected 60 min after pollination. Pollen grain germination and pollen tube growth were studied with normal microscopy of squash preparations of pistils in aniline blue.

Onset of pollen germination was variable in all individual crosses, but was similar in all selfings (see table). Maximum pollen germination was obtained with selfing. Pollen germination in all reciprocal crosses except IR36/IET7301 differed considerably.

individual floret varied. In some crosses, 20-30 pollen grains could be seen on the stigma; in others, only 5-6. Emergence of pollen tubes on the bifurcated hairy stigma occurred immediately after pollen grains had landed on the stigma. After penetrating the papillated stigma hairs, the tubes grew through these hairs into the style (see figure).

Styles were quite long and the pollen tubes could not be traced up to the base (staining became faint as pollen tubes worked their way toward the ovary). Pollen tube growth differed considerably in the reciprocal crosses. There was no abnormal pollen tube growth and no evidence of pollen tube and maternal tissue interaction hindering growth.

Overall, seed set was quite poor. Maximum seed set was with selfing.

Pollen fall on stigmas of each

29.8 (4) 35.2 (2) 34.8 (3) 35.7 (1) 17.2 (8) 02.6 (16) 04.6 (14) 24.7 (7) 07.8 (13) 08.9 (10) 25.4 (6) 08.3 (12) 08.5 (11) 03.3 (15) 29.2 (5) 10.2 (9)

Normal pollen tube growth of IET7301/Pant Dhan 4 10 min after pollination. Pantnagar, India.

Pollen germination was correlated more directly with seed set and was not affected by the rate of pollen tube growth (see table). Seed set was highest in IET7301/IET7301: that cross had the third highest pollen germination and ninth longest pollen tubes.

correlation. When IR36 was crossed with Pant Dhan 4, pollen germination was 55.5% and seed set was 17.2%; in the reciprocal cross, pollen germination was 19% and seed set, 2.6%.

The reciprocal crosses confirmed that

IRRN 14:4 (August 1989) 7

This suggests that chromosomal abnormalities are not the cause of low seed set in intraracial crosses of rice. Inadequate pollination or low pollen germination seemed to be the causes. Rate of pollen tube growth and length of pollen tube seem to have no relationship to seed set.

Cell division in indica rice varieties

M. Selvanathan and V. K. Khanna, Plant Breeding Department, G. B. Pant University of Agriculture and Technology, Pantnagar, India

We studied the relationship between chromosomal behavior, pollen development, and seed set in four indica rices: IR36, Pant Dhan 4, Rasi, and IET7301.

The mitotic index was very poor, indicating a slow rate of cell division (see table). Mitotic cells revealed a single nucleolus. Chromosomes were extremely small. Cells were few at metaphase, anaphase, and telophase and plentiful at interphase and prophase stages. Cell division was normal.

Chromosome behavior was normal at prophase, without heteromorphic bivalents, bivalents with a terminal fold, rod bivalents, univalents, quadrivalents, stretched chromosomes, etc. Loose pairing was not discernible. Successive stages of synizesis, zygotene, pachytene, diplotene, and early diakinesis showed the budding of the nucleolus.

As the secondary nucleolus became larger, the primary nucleolus became smaller. Leptotene stages showed beaded threads. Usually two threads were attached to the nucleolus.

Mitotic index, pollen sterility, and seed set in different rice cultivars.

Mitotic Pollen Seed

(%) Cultivar index sterility (%) set

At zygotene, chromosomes were in pairs but could not be counted. At diplotene, budding of the nucleoli with a few twisted bivalents could be seen. At diakinesis, the chromosomes were condensed further, some ring chromosomes could be seen, and the nucleolus gradually decreased in size before it disappeared.

Several small nucleolar bodies known as supernumerary nucleoli were found, usually 2-6 per cell, but up to 18 in some cases. At metaphase I, anaphase, and

telophase, chromosomal behavior was normal.

were found, pollen sterility (highest in Rasi and lowest in IR36) may be attributable to genic causes. Seed set was lowest in IR36. Pollen sterility showed no correlation with seed set.

It appears highly improbable that chromosomal irregularities cause low seed set in rice. Inadequate pollination or low pollen germination could be the problem.

Though no chromosomal aberrations

Breeding methods sterile (WA-MS) line Zhen-Shan 97A in order to eliminate panicle enclosure of

Transfer eui gene to WA-MS line Zhen-Shan 97A (Oryza sativa ssp. indica) and eliminating its panicle enclosure

Shen Zongtan and He Zuhua, Zhejiang Agricultural University, Hangzhou, China

We studied the interaction between the eui gene of uppermost internode stock and cytoplasm of wild abortive male

the A line.

Shan 97A and B lines by backcross breeding (see figure).

97-eui A and B lines (610A and 610B, 612A and 612B, 618A and 618B) have been bred (see table). Compared with the parents Zhen-Shan 97A and B, mean panicle exsertion (PE) of new lines A and B is longer, exserted stigma percentage is higher, and plants are taller.

The eui gene was transferred to Zhen-

Three new semidwarf MS Zhen-Shan

IR36 4.00 ± 1.00 15.33 ± 6.50 29.8 Pant Dhan 4 4.33 ± 1.52 20.00 ± 2.64 35.2 Rasi IET7301 3.66 ± 0.57 16.00 ± 4.35 35.7 Breeding procedures for sterile lines 610A and 612A with exserted panicles and their

4.34 ± 2.51 21.00 ± 3.00 34.8

maintainers (breeding lines 618A and B).

8 IRRN 14:4 (August 1989)

The new A lines are shorter than B and restorer, which would help pollen dispersal on A plants in seed production. The correlation between PE and uppermost internode length was positive ( r = 0.9655**) and plant height ( r = 0.4474**) in the eui plant.

The study also showed that some minor genes modified the eui gene. That facilitated selecting eui A and B lines with suitable PE. Gibberellic acid would not be needed in seed production of the new A lines, significantly reducing seed production costs.

Performance of hybrid rice in Indonesia

O. Suherman, Maros Research Institute for Food Crops, South Sulawesi, Indonesia

We compared yields of hybrid rices and high-yielding conventional varieties in Jul-Oct 1987. Trial entries were hybrid rices 11-32A/Ce64, L301A/ R29, V20A/ IR54, and V20A/ Sadang, and popular high-yielding varieties IR36 and IR64. The trial was in a randomized complete block design with six replications.

The crop was intensively managed: hand weeding, optimum water, and complete pest and disease protection. Fertilizer was 120 kg N as urea and ammonium sulfate, 45 kg P, and 45 kg K/ ha. N was applied 1/3 at planting,

Stubble planting - promising vegetative propagation method for hybrid rice

M. Mahadevappa, Vishakantha, N. D. R. K. Sarma, and K. G. Govindaraj, University of Agricultural Sciences, GKVK, Bangalore 560065, India

A major constraint in commercializing rice hybrids has been seed production (A line and hybrid). Seed set of 25-30% on the female line results in poor hybrid seed yields.

propagation as an economical seed We studied the feasibility of vegetative

Some characters of new MS lines and maintainers. Guangzhou, China, 1988.

Plant Exserted

(cm) (%) Line Genotype PE a (cm) height stigma

610A CMS ( eui eui ) –4.2 ± 1.7 72.9 >90 610B F ( eui eui ) 5.3 ± 1.9 80.0 –

612A 612B

618A 618B

CMS ( eui eui ) –1.8 ± 2.2 74.9 >90 F ( eui eui ) 6.6 ± 1.4 84.8 –

CMS ( eui eui ) –3.4 ± 2.1 72.4 >90 F ( eui eui ) 5.7 ± 1.7 79.0 –

Zhen-Shan 97A (CK1) CMS ( Eui Eui ) –9.5 ± 3.5 60.7 30-50 Zhen-Shan 97B (CK2) F ( Eui Eui ) 1.1 ± 2.1 72.8 eui stock (CK3) F ( eui eui ) 25.9 ± 4.4 136.3 –

a Mean PE of all tillers of a single plant.

–

Grain yield, yield components, and agronomic traits of 4 hybrid rices and 2 high-yielding rice varie- ties. Maros, Indonesia, 1987 dry season.

Grain yield Panicles 1000- Unfilled Grains/ Entry (t/ha at (no./m 2 ) grain grains/ panicle height

Plant Duration

14% moisture) wt (g) (%) (no.) (cm) (d)

II-32A/Ce64 L301A/R29 V20A/IR54 IR64 V20A/Sadang IR36

LSD (0.05) (0.01)

CV (%)

6.7 5.5 5.4 5.2 5.1 4.3

1.5 2.0

23.5

308 272 308 313 296 396

68 92 18

24.2 19.2 140 24.8 12.8 131 24.3 15.8 124 24.9 14.9 116 26.3 18.7 129 20.4 20.1 134

2.6 5.2 22 3.5 7.0 30 8.9 25.8 14

87 81 78 91 83 76 8

11 8

110 95

100 105 115 115

– – –

2/3 at 30 d after planting. numbers tended to be high. Unfilled

significantly higher grain yield than different from that of IR36. IR36 (see table). The hybrids had fewer II-32A/Ce64 is 10 cm taller and panicles/m 2 but heavier grains. Spikelet matured 5 d earlier than IR36.

Only hybrid II-32A/ Ce64 produced grain percentage was not significantly

production method. The advantages of vegetative propagation are that 1) need for fresh hybrid seed is reduced; 2) duration of a vegetatively propagated crop usually is less than that of a main crop; and 3) crop establishment savings are realized.

Vegetative propagation methods include ratooning, stubble planting, and tiller separation and planting. Stubble planting appears to be most promising.

During 1987 wet season, we studied 190 genotypes’ response to ratooning, stubble planting, and tiller separation and planting. There was considerable genotypic variation. In 1988 dry season,

we evaluated 17 experimental hybrids in a multilocation trial. Thirteen showed good regeneration. Two of three replications were used to evaluate ratoonability and one to evaluate stubble planting. The sprouted stubbles of 10 of the 13 hybrids that showed better regeneration were uprooted, cut back to 10-12 cm height, and planted individually. A transplanted crop of Mangala (a short-duration variety) was used as check. Mangala seedlings were raised so that the transplanting coincided with stubble planting. The 11 treatments were laid out in a randomized block design with four

IRRN 14:4 (August 1989) 9

Performance of rice hybrids in main, ratoon, and stubble planting. Bangalore, India.

Days to 50% flowering Yield (t/ha) Hybrid

Main Ratoon Stubble Main Ratoon Stubble crop crop crop crop crop crop

IR54752A/IR46R IR54752A/IR28178 IR54752A/IR54 IR6830A/IR9761 IR6830A/IR21916 IR6830A/IR29723 IR6830A/IR19058 IR6830A/IR13419 IR6830A/IR29512 IR6830A/IR25912 IR6830A/IR19392 IR6830A/IR64R Madhu WA/Mily 54 IR46828A/IR2863 IR54752A/ARC11353 IR46828A/ARC11353 Madhu WA/IR28210

Check Jaya Mangala Pushpa

107 105 111

94 107 118 102 111 115 113 120 104

98 98

110 94 98

113 94

102

94 94 96 94 96 90 98 90 90 90 94 86 – –

96 – –

– – –

118 121 121

122 109

116 119 119 121

–

–

– –

120 –

– –

– – –

9.8 8.8 8.3 8.2 8.1 7.8 7.5 7.3 7.2 7.2 7.1 6.7 6.6 6.2 6.1 5.1 3.2

6.7 6.6 5.7

3.4 2.1 3.9 1.2 1.0 1.0 0.9 2.6 2.6 1.3 1.0 0.8

– –

4.1 – –

– – –

4.8 3.6 6.8

3.4 2.1

4.4 2.7 2.2 2.9

–

–

– – –

6.9 – –

– 4.3

(seedling planted)

Since the stubbles were cut back to 10-12 cm height at planting, actual growth duration of the a At planting, stubbles were 40-45 d old. Hence, days to 50% flowering are more in the stubble crop.

stubble crop (from planting to harvesting) is less than that of the main crop.

replications. The test plots were topdressed with 50 kg N/ha 35 d after planting.

Hybrid IR54752A/ARC11353 had highest yield (6.92 t/ha), closely followed by IR54752A/ IR54R (6.82 t/ha) (see table). The increased yield is due mainly to higher total and filled spikelets and, to some extent, more panicles per unit land area. Further research is needed to establish the best maturity stage for harvesting the main crop and the age of stubble at planting to get better stubble regeneration and stubble crop performance.

The International Rice Research Newsletter is mailed free to individuals and institutions engaged in rice research and training. For further information, write IRRI, Communication and Publications Dept., Division R, P. O. Box 933, Manila, Philippines.

Performance of F 1 hybrids Jammu and Kashmir

in

J. S. Bijral, T. R. Sharma, B. Singh, B. B. Gupta, and K. S. Kanwal, Sher-E-Kashmir University of Agricultural Sciences and Technology, Regional Agriculture Research Station (RARS), R.S. Pura 181102, India

We evaluated the yield potential of nine F 1 hybrids in 1988 wet season. Seedlings (30-d-old) were transplanted in 4.32-m 2

plots at 30- × 20-cm spacing in a randomized block design with three replications. All plots were fertilized at 100-60-30 kg NPK/ha.

The F 1 hybrids were compared with the best commercial check, Jaya. Data on grain yield, primary yield components, and related attributes were recorded and standard heterosis calculated. Net plot size 2.40-m 2 was used to estimate grain yield. Positive

standard heterosis in yield ranged from 4.96 to 109.9%. Only three hybrids (RHR1, RHR2, and RHR6) yielded significantly higher than Jaya (see table).

The increase in yield was due mainly to positive standard heterosis in panicle number/m 2 , total biomass, harvest index, and grain weight. All hybrids except RHR9 showed significant negative standard heterosis in spikelet fertility.

Standard heterosis for yield and yield components of F 1 hybrids at RARS, R. S. Pura (J&K), India.

Grain Standard heterosis b (%)

(t/ha) Yield Panicles/m 2 Spikelets/ Spikelet 1000- Total Harvest Hybrid a Cross combination yield

panicle fertility grain biomass index weight

RHR1 Zhen Shan 97A/IR31868 7.7 41.36* 12.50* 11.24 –9.75* 4.80 19.14* 18.55* RHR2 V20A/IR31802 8.0 47.06* 30.36* 2.46 –12.71* 16.16* 21.80* 20.84* RHR3 Zhen Shan 97A/IET8585 6.4 16.73 29.46* 38.81* –7.81* 0.44 2.27 14.10* RHR4 Zhen Shan 97A/IR31802 3.4 –36.58* 9.82 –40.40* –17.99* –10.0 4 2.66 –15.08* RHR5 Zhen Shan 97A/IET1410 5.2 –3.49 9.82 –34.54* –12.97* 10.92* –19.90* 20.54* RHR6 Zhen Shan 97A/VL 15 11.4 109.90* 38.39* 6.79 –13.88* 22.27* 76.66* 18.86* RHR7 V20A/IR31851 6.9 26.65 11.61* –28.80* –15.71* 14.85* –0.3 4 27.03* RHR8 IR48483 A/IR83619 6.3 15.63 –3.57 6.56 –5.91* 6.55 12.7 2 2.57 RHR9 IR46830 A/IR36 5.7 4.96 37.50* –30.44* –0.54 6.55 2.34 2.68 Jaya (check) 5.4

LSD (0.05) 1.5 20.67 26.32 3.73 1.52 12.29 4.54

a RHR = Ranbir Hybrid Rice. b * = significant at 5% level.

10 IRRN 14:4 (August 1989)

S. O. W. M. Reuben and S. D. Katuli, Sokoine University of Agriculture, Box 3005 Morogoro, Tanzania

To help schedule N fertilizer topdressing, we studied panicle initiation in wet and dry seasons in 19 recommended semidwarf and tall indica rices of different durations. Starting from 30 d before estimated heading date, a large number of healthy tillers

Nellore district commonly experiences typhoons in Oct-Nov, when the rice crop is in maximum tillering to panicle initiation. In Nov 1984 wet season, gales with winds of 100-120 km/ h lashed coastal parts of Nellore district for nearly 60 h, severely damaging rice foliage.

Path analysis of yield components and selected agronomic traits of upland rice breeding lines

from about five good hills were cut at the plant base every other day. The tillers were dissected for panicle initiation.

The panicle initiation and flowering interval appears to be a varietal characteristic dependent on duration and season (see table). Because of that, determination of panicle initiation for topdressing N should be based on actual plant dissection. Sampling dates should be calculated from estimated heading date, generally 30-35 d after panicle emergence in the tropics.

G. V. Reddy, V. D. Naidu and P. S. Reddy, Andhra Pradesh (AP) Agricultural University, Agricultural Research Station, Nellore 524004, AP, India

Time of panicle initiation and flowering in some rice varieties

Damage varied among varieties. Some showed severe damage, with the leaf blade shredded lengthwise, starting from tip down, combined with necrotic streaks. (The damage resembled that of

bacterial leaf streak.) Local predominant variety NLR9672 suffered nearly 20% leaf damage.

Only a few of 90 varieties showed resistance to wind damage (see table).

Yield potential

Varietal response to typhoon injury in Nellore, Andhra Pradesh, India

C. Kundu, B. K. Mandal, and A. Ghosh, Rice Research Station, Chinsurah 712102, India

Entries showing resistant reaction to wind damage. Nellore, AP, India, 1984.

Entry

NLR9672 GEB 24 NLRT105 MTU7029 BCP3 BCP4 BCP5 Mahsuri NLR26706 NLRT62 NLRT71 NLRT76 NLRT78 NLR3079 NLRT80 NLRT87 NLRT85 NLRT88 NLRT91 NLRT97 NLRT99 NLRT98 NLRTl00 NLRT103 NLR28545 MTU6861 IRl554-239-3-3 IR19660-274 IR40 IR32 ET5656 IR38 Sudwee Tetep Tadukan

Wind damage

(%)

20 0 0 1 2 2 2 2 2 2 2 5 5 2 5 2 2 2 2 5 2 2 5 5 5 2 2 2 5 5 2 2 5 5 5

Damage score a

(0-9 scale)

5 0 0 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

a 0 = no injury, 1 = less than 1%, 3 = 2-5%, 5 = 6-25%, 7 = 26-50%, and 9 = 51-100%.

Panicle initiation and flowering in 19 rice varieties. Chinsurah, India. -

Panicle Flowering Panicle initiation (d after initiation to

Variety photoperiodism (d after seeding) seeding) flowering (d)

Wet Dry Wet Dry Wet Dry

Duration and

CR237-1 CNM25

IET1444 Cauvery IR50 IET4094 Ratna IR36 IET2254 IET2815 IET5656 Pankaj Latisal Kalma 222 Kumargore NC3 24 Radhunipagal NC6 78

CR126-42-1

Short Short Short Short Short Short Short Short Short Medium Medium Long Long Photoperiod sensitive Photoperiod sensitive Photoperiod sensitive Photoperiod sensitive Photoperiod sensitive Photoperiod sensitive

46 97 60 111 14 14 57 111 72 127 15 16 59 111 75 131 16 20 57 110 73 131 16 21 60 108 76 127 16 19 63 114 80 133 17 19 65 116 82 137 17 21 65 118 83 138 18 20 70 117 88 138 18 21 75 124 93 143 18 19 69 118 86 137 17 19 96 122 116 142 20 20 96 129 117 151 21 22 96 116 119 134 23 18 98 120 120 137 22 17 97 120 118 138 21 18 96 114 117 133 21 19 95 117 117 136 22 19 99 119 121 138 22 19

We examined direct and indirect associations between selected variables in 11 advanced upland rice breeding lines (Farox 229, IRAT104, IRAT156, IRAT161, IRAT170, ISA6, ITA128, ITA235, ITA305, ITA315, OS6) and local check Supa. The trial was laid out during the 1987 cropping season in a

IRRN 14:4 (August 1989) 11

Relationship of rainfall distribution patterns to rice productivity

R. Srivastava, National Bureau of Soil Survey and Land Use Planning, Nagpur, M.S., India; and O. Prakash, Soil Science Department, G. B. Pant University of Agriculture and Technology, Pantnagar, U. P., India

We studied the effect of rainfall distribution patterns on rice yields using second degree multiple regression equation. Average yields 1970-84 (15 yr) at Pantnagar Rice Growing Farms and weekly data on rainfall during the rice- growing season collected from Meteorological Observatory, Pantnagar, were used.

The rice-growing season, covering approximate1y 168 d from 21 May to 4 Nov, was divided into 24 7-d periods.

The season also was broadly divided into five distinct physiological growth stages: nursery and transplanting 21 May-24 Jun, active vegetative growth 25 Jun-5 Aug, lag vegetative growth 6 Aug- 2 Sep, reproductive stage 3-30 Sep, and ripening 1 Oct-4 Nov.

The second degree multiple regression equation between rice yield and weekly total rainfall was

Where Z = rice yield in quintals/ ha (1 quintal = 0.1 ton; t i = a 7-d period (1 for the week 21-27 May and 24 for the week 29 Oct-4 Nov); x i = total rainfall within any given 7-d period; T= year (1 in 1970 and 15 in 1984). T was included to correct for long-term trend in yield.

Path coefficient analysis of phenotypic correlations on the direct (diagonal) and indirect (off diagonal) effects of the components of yield on grain yield of upland rice lines. a Morogoro, Tanzania, 1987.

Variable

Plant height Days to maturity

Panicle length Tillers/plant Panicle weight % filled grains/panicle Panicles/m 2

1000-grain weight Plants/m 2

Days to maturity

–0.154 –0.095 –0.079 –0.068 0.004 0.004 0.077 0.030 0.043

Plant height

0.471 0.770 0.347

0.030 –0.117 –0.210 –0.133 –0.287

–0.130

Indirect via

Panicle Tillers/ length plant

–0.451 0.189 –0.396 –0.072 –0.878 0.108 –0.222 0.427 –0.229 0.04 1 –0.357 0.053 –0.206 0.268

0.617 –0.158 0.264 0.258

Panicle weight

0.000 –0.003 –0.003 –0.001 –0.010 –0.009

0.001 0.003

–0.001

% filled grains/ panicle

–0.025 –0.159

0.425 0.129 0.911 1.045 0.038

–0.375 0.243

Panicles/ 1000-grain m 2 weight

0.228 –0.023 0.125 –0.021

–0.107 –0.084 –0.287 –0.045

0.051 –0.033 –0.016 –0.043 –0.457 –0.024

0.090 0.120 –0.330 –0.017

Plants/ m 2

–0.136 –0.181 0.146 0.294 0.043 0.113 0.351

–0.068 0.486

Total correlation, rp, with yield

0.099 0.029

0.097 0.808** 0.672*

0.126 0.131

–0.125

–0.163

a Residual effect = 0.200. *, ** denote significance at P < 0.05, 0.01, respectively. Underlined figures indicate direct effects.

randomized complete block design with three replications.

Filled grains/panicle and plant height had high positive direct effects on grain yield (see table). The independent effect of panicle length on yield was strong and negative. Plant density and tillers/plant, had moderate positive direct

effects on grain yield; the effect of panicles/m 2 was moderately negative. High correlations of panicle weight and yield were predominantly through filled grains/panicle.

The path analysis suggests the importance, in order, of filled grains/panicle, plant height, plant

density, and tillers/plant in grain yield of the upland rice lines. Relationships between filled grains/ panicle and plant height and plant height and plants/m 2

and tillers per plant were negative, suggesting a compromise in selecting for the optimum combination of these characters.

Relationship between grain yield and light transmission in rice

R. Sadasivam, A. Arjunan, S. Mohandass, and M. Nagarajan, Crop Physiology Department, Tamil Nadu Agricultural University (TNAU), Coimbatore 3, Tamil Nadu, India

We transplanted 25-d-old seedlings of 15 short-duration rice varieties 6 Jul 1988 at 20- × 10-cm spacing. Data on light intensity at the top and bottom of the canopy were collected at flowering,

using Line Quantum Sensor. A highly significant negative correlation was found between light transmission and grain yield (see figure). Ten percent light

Relationship of light transmission to grain yield in 15 short-duration rice cultivars. Coimbatore, India, 1988 wet season.

12 IRRN 14:4 (August 1989)

transmission at flowering was optimum. Light transmission ratio can be used as one criterion for selecting high-yielding rice cultivars.

1. Effect of 1-mm rainfall above average weekly total rainfall on rice yield for each 7d period, 21 May-4 Nov.

Selecting for photoperiod sensitivity in pedigree nurseries

A. M. Pamplona and D. J. Mackill, Plant Breeding Department, IRRI

Photoperiod sensitivity is an important character in many rainfed lowland rice- growing areas, particularly where the rainfall pattern is erratic. But a problem in breeding photoperiod-sensitive cultivars is that often only one generation can be grown a year, doubling the time needed to develop advanced lines.

We seeded breeding lines in the pedigree nursery in the first week of Jun in wet season (F 5 ) and in mid-Dec in dry season (F 6 ). Strongly photoperiod- sensitive F 6 lines were identified as those that did not flower within 5 mo when seeded in a special mid-Feb nursery. At Los Baños, Philippines (14° N), photoperiod-sensitive lines seeded in Feb will not flower until the following wet

2. Actual and predicted rice yields for different years using the rainfall equation.

Rainfall 1 mm above the average 12 kg/ha. weekly total during active and lag Predicted yields for different years, vegetative growth stages had a positive using weekly total rainfall data, were effect on yield; during the other stages, compared with actual yields (Fig. 2). its effect was negative (Fig. 1). The The coefficient of correlation between adverse effect of above average rainfall actual yield and predicted yield was was more pronounced late in the 0.758, significant at the 0.01 level. ripening stage, when it reduced yield 10-

1. Relationship between flowering days of F 5 lines grown in wet season (WS) (seeded 5 Jun 1986) and the resulting F 6 lines grown in dry season (DS) seeded 17 Dec 1986. Photoperiod- sensitive lines are those that did not flower when seeded in February.

season (Sep or later), when daylengths lines seeded in Jun flowered late. When shorten. the resulting F 6 lines were seeded in

Most of the photoperiod-sensitive F 5 Dec, they flowered early (Fig. 1). The

IRRN 14:4 (August 1989) 13

S. S. Malik, Haryana Agricultural University, Regional Research Station, Uchani, Karnal, India

Grain quality of some promising rice genotypes

Relationship between flag leaf angle and grain yield in 15 rice cultivars. Coimbatore, India, 1988 wet season.

photoperiod-sensitive lines can therefore be identified in segregating generations by a large difference in flowering duration between seasons. Insensitive lines have similar growth durations in different seasons.

Most of the improved photoperiod- sensitive lines selected in the pedigree nursery seeded 5 Jun (wet season) flowered in mid-Oct (Fig. 2). This flowering period should be suitable for large areas of rainfed lowland rice.

2. Distribution of flowering dates of photoperiod- sensitive pedigree lines (F 5 -F 6 ) seeded on 5 Jun 1986.

Relationship between grain yield and flag leaf angle in rice

R. Sadasivam, A. Arjunan, S. Mohandass, and M. Nagarajan, Crop Physiology Department, TNAU, Coimbatore, Tamil Nadu, India

We grew 15 short-duration rice cultivars during 1988 wet season, in a randomized block design with three replications. Seedlings (25-d-old) were transplanted 6 Jul at 20- × 10-cm spacing. The flag leaf angle was measured at panicle emergence.

negative correlation between flag leaf angle and grain yield (see figure). Flag

There was a highly significant

14 IRRN 14:4 (August 1989)

leaf angle at panicle emergence could be an alternate selection index for higher yield potential.

The International Azolla Newsletter is published for researchers in the development and application of azolla in rice production. Its content focuses on discussions of current issues; it does not publish research reports. For more information, write Dr. I. Watanabe, Azolla Newsletter editor, IRRI, P.O. Box 933, Manila, Philippines.

Grain quality and nutritional value

In 1985, we tested 25 promising rice varieties and strains for hulling, milling, and head rice recovery; grain length, breadth, and L/ B ratio; alkali value (0- 9); and elongation ratio. The alkali digestion test was done with 10 grains of

Grain and quality characteristics of some promising rice genotypes. Karnal, India, 1985.

Brown Milled Head rice Milled grain Genotype rice rice recovery Alkali Elongation

(%) (%) (%) Length Breadth L/B value ratio (mm) (mm) ratio

Basmati 370 Pakistani Basmati Punjab Basmati Pusa 150 HKR221 Sonalee T 3 dwarf mutant HKR222 Ratna IR36 Palan 579 Prasad IET4141 PR106 PR107 IR8 Jaya Pusa 2-21 Jhona 349 HKR1 HKR101 HKR207 HAU10-221-1-5 HAUK12-20-4-2 IR5853-118-5

Mean CV (%)

77.2 68.7 53.2 6.7 1.8 3.7 2 1.8 77.7 68.5 53.1 7.0 1.8 3.8 3 2.0 80.0 68.3 44.4 6.7 1.8 3.8 6 1.6 77.7 63.3 40.0 6.3 1.8 3.4 6 1.8 71.5 65.3 40.8 7.0 1.8 3.9 4 1.6 74.0 60.5 34.8 7.1 1.7 4.1 6 1.4 85.0 63.8 47.5 6.0 1.7 3.6 5 80.1 69.2 50.2

1.7 6.5 1.7 3.8 4 1.6

77.0 68.5 51.4 6.2 1.7 3.6 4 1.7 79.7 69.6 47.0 6.2 1.8 3.5 4 1.5 80.6 69.6 47.3 6.0 1.8 3.3 4 1.5 85.2 75.4 54.7 6.1 1.7 3.6 4 1.5 78.8 68.4 54.8 5.8 1.9 3.0 5 1.3 79.0 67.2 60.7 5.8 1.8 3.2 6 1.4 82.4 72.4 58.2 6.2 1.9 3.3 6 1.4 78.4 68.2 51.2 6.7 2.1 3.1 6 1.3 81.4 70.2 55.6 6.8 2.2 3.2 6 1.3 82.0 70.0 64.8 5.2 2.0 2.7 7 1.2 81.4 67.2 62.2 5.7 2.0 2.9 5 1.4 81.0 66.4 45.8 5.6 1.9 3.0 7 1.2 84.5 70.3 42.2 6.3 2.1 3.0 7 1.3 77.0 66.4 39.8 7.0 1.8 3.8 4 1.4 83.7 69.8 52.5 6.8 1.7 3.9 4 1.6 81.2 66.0 52.1 6.0 1.8 3.3 5 1.5 80.8 66.6 52.6 6.2 2.0 3.1 4 1.5

79.9 68.0 50.3 6.3 1.8 3.4 – 1.5 5.2 7.4 8.5 2.3 2.1 – – –

each strain in 10 ml (l.7%) KOH solution for 23 h.

Prasad had the highest brown rice

had the lowest head rice recovery and ratio and elongation ratio. Pakistani the highest L/B ratio. Basmati had the highest elongation

Although L/B ratio was inversely ratio, followed by Basmati 370. The and total milled rice yields (see table). associated with head rice recovery, there lowest alkali spreading value was in Pusa 2-21 had the highest head rice seems to be no association between L/B Basmati 370. recovery and lowest L/B ratio. Sonalee

Modified single grain analysis for gel consistency

S. X. Tang, G. S. Khush, and B. O. Juliano, IRRI

Gel consistency is a good index of cooked rice texture, especially in high- amylose rices. We modified Cagampang’s method and Zaman’s single grain procedure to develop a reliable single grain analysis for gel consistency. Analysis of the gel consistency of nine rices with hard (27- 40 mm), medium (41-60 mm), and soft (61-100 mm) gel consistency showed that modified single grain analysis is a reliable procedure (see table).

These are the major steps in the procedure:

The embryo is carefully removed from milled kernel with a blade and the single grain ground to a fine powder (100 mesh) in a Wig-L-Bug amalgamator using plastic tube for 15 s.

into a 10- × 75-mm test tube and 3 A 10-mg sample of powder is put

Comparison of gel length using bulk seed method (100 mg rice powder, 13 × 100 mm test tube) and modified single grain analysis (10 mg rice powder, 10 × 75 mm test tube).

Gel length a (mm)

Bulk seed Single grain Genotype

Hard gel IR58 31.1 ± 0.6 18.8 ± 0.4

IR42 31.2 ± 0.3 19.3 ± 0.3 IR37865-29 31.4 ± 0.7 19.1 ± 0.3

Medium gel IR28224-3 42.0 ± 1.8 25.8 ± 0.7 IR48 50.8 ± 1.4 31.3 ± 1.2

Soft gel IR13754-5 74.4 ± 2.3 46.3 ± 1.7 IR29723-143 95.5 ± 1.8 55.1 ± 1.2 IR33043-46 91.9 ± 1.8 54.2 ± 1.3 IR32 100.0 ± 0.0 59.0 ± 0.9

a Mean of ten replications ± standard error.

drops (0.026 ml) of 95% ethanol containing 0.025% thymol blue are added.

stirring in a Vortex Genie.

immediately and the content stirred well again.

The test tube is covered with glass marble and placed over a boiling water bath for 6 min (tube contents should reach 1/2-2/3 the height of the tube).

The contents are mixed well by

0.26 ml of 0.2 N KOH is added

Disease resistance

Relationship between tungro (RTV) and sheath rot (ShR) in three rice cultivars

V. D. Naidu and P. S. Reddy, Andhra Prodesh (AP) Agricultural University, Agricultural Research Station (ARS), Nellore 524004, A P, India

In summer 1985, we observed a close relationship between RTV and ShR incidence in rice cultivars Srinivas (IET2508), NLR13969, and Rasi. Dwarfing symptoms with yellowing was observed in all the cultivars. RTV symptoms were moderate on Srinivas and NLR13969 and light on Rasi.

RTV-affected plants in all three cultivars showed severe ShR incidence at maturity. In cultivars free of RTV, ShR incidence was only 5-8% (see table).

The difference in ShR incidence on plants with and without RTV symptoms was significant. Higher incidence of ShR in RTV-affected plants could be due to easy entrance of the ShR pathogen into physically weak hosts.

The test tube is cooled at room temperature for 5 min, then transferred to an ice-water bath for 15 min.

The chilled test tube is placed horizontally on a table for 30 min.

Total length of gel flow is measured in mm from the bottom of the tube to the end of the gel.

Gel is classified as hard (16-23 mm long), medium (24-36 mm), and soft (37- 60 mm).

ShR incidence in plants with and without RTV infection symptoms. ARS, Nellore, India, 1985.

Cultivar RTV ShR

symptoms (%)

Srinivas Without 8 Srinivas With 30 NLR13969 Without 6 NLR13969 With 36 Rasi Without 5 Rasi With 17

LSD (0.05) 4

Reaction of some promising rice cultivars to grassy stunt virus (GSV)

N. R. Bai, R. Devika, S. Leenakumary, and C. A. Joseph, Rice Research Station, Kerala Agricultural University, Moncompu, Kerala, India

GSV caused severe damage to rice during 1988 wet season (Jun-Jul to Oct- Nov) in Kuttanad. The virus also was reported in India in 1969, 1973-74, and 1984.

cultivars in the Preliminary Variety Trial (All India Coordinated Rice Improvement Project) planted at the

We evaluated 49 promising rice

IRRN 14:4 (August 1989) 15

Moncompu Rice Research Station. The experiment was laid out in a randomized block design with two replications. Seedlings were planted at 20- × 15-cm spacing and the plot fertilized with 70-35-35 kg NPK/ha in three splits.

Cultivars were affected by GSV at maximum tillering. Incidence was heavy, in some plots all plants died.

None of the 49 cultivars in the test showed resistance to GSV (see table). Seven showed moderate resistance, 14

were moderately susceptible, 4 were susceptible, and 24 were highly susceptible.

Virulence of six isolates of Xanthomonas campestris pv. oryzae on rice

Y. Suryadi and T. Tjubarjat, Sukamandi Research Institute for Food Crops, Subang, West Java, Indonesia

We studied the virulence of six isolates of X. campestris pv. oryzae, the causal organism of rice bacterial blight (BB), on four improved rice cultivars in the screenhouse 1987 and 1988 wet seasons.

Cultivars were inoculated 45 d after

transplanting by pricking the uppermost fully extended leaves with a bacterial suspension of each isolate adjusted to 10 9 CFU/ml. Length of lesion on inoculated leaves was measured 21 d after inoculation.

Lesion length indicated that isolates differed significantly in pathogenicity and cultivars showed different susceptibilities (see table). Isolate Si 8524, representing Indonesian group IV, was the most virulent. IR64 and Dodokan (released in 1987) showed good resistance against BB isolates.

Field resistance to false smut (FS) and narrow brown leaf spot (NBLS) in eastern Uttar Pradesh

R. N. Singh and A. T. Khan, N. D. University of Agriculture and Technology, P. O. Dabha Semar, District Faizabad 224133, Uttar Pradesh (UP), India

FS caused by Ustilaginoidea virens (Cke.) Takahashi and NBLS caused by

Cercospora oryzae Miyake are important diseases in eastern UP. We tested 231 rice genotypes for resistance during 1986-87 and 1987-88 hot wet seasons (1 Jun-30 Nov). Natural disease pressure was high in both years. All trial plots were irrigated and fertilized with 120-60-60 kg NPK/ha. Disease was rated by the Standard evaluation system for rice, at the dough stage for NBLS and at the hard dough to maturity stage for FS.

Susceptibility of promising rice cultivars to GSV. Moncompu, India, 1988 wet season.

Disease Cross score

(0-9)

IET10512 IET10513 IET11057 IET11058 IET11060 IET11062 IET11063

IET11064 IET11066 IET11067 IET11068 IET11069 IET11070 IET11071 IET11072 IET11073 IET11074 IET11075 IET11076 IET11077 IET9381 IET11579 IET11580 IET11581 IET11582 IET11583 IET11584 IET11585

IET11586 IET11587 IET11588 IET11101 IET11589 IET11590 IET11591 IET11592 IET11593 IET11594 IET11595 IET11596 IET11597 IET11598 IET11599 IET11600 IET11601 IET11602 IET11603

– –

3 2 3 8 3 2 5

8 5 8 5 5 8 9 9 9 8 8 8 8 9 5 7 7 4 7 3 9

3 9 4 4 9 4 4 8 9 9 9 9 8 9 9 5 7 4 4 8 4

IET2815/Khonorollo RP79-9/Salumpikit Rasi/IET7332 Rajendra/IR30 Mashuri/Jaya

IR30/Babawa//

TKM6/IET1444 Phalguna/TKM6 Sabarmati/Sona

IR8/IET4141

Jaya/IET4146 IET4107/WGL22245 IR8/Surekha IR8/Surekha IR8/Surekha IR8/Surekha Rasi/Gampai IR1561/Ptb 33 Co 13/IR26 ADT32/ADT29 Rajendra/IR30 IR36/MTU4569 BAM3/TN1 OR5461/RNR32341 WGL 27120/MTU//

W17620/Surekha Ratna/ARC5981 Sona/K118 Mutant of Luchai - 12 A23/TR17

B 29826/SR 62-31-4

IR2071-625-1-25-2

CR44-35/W12708

Pusa 2-21/WGL 28171

IET4699/RP193-1 IET4699/RP193-1 IET4699/RP193-1 Jaya/Gampai IET7302/IET7575 Sona/ARC14529 Ratna/Ptb 33

IET2815/Latisail Rasi/Gampai

Sona/ARC5981 IET7302/IET7575 Ratna/ARC5981 Swarnadhan/Benong Swarnadhan/Tamiang Swarnadhan/Salamat Jaya (check) Local (check)

BB lesion length on 4 rice cultivars at 21 d after inoculation. Sukamandi, 1987 and 1988 wet seasons.

Lesion length a (cm)

IR64 IR48 Dodokan TN1 Mean b Isolate

16 IRRN 14:4 (August 1989)

Si8505 Si8524 Si8401 Si8501 Si8603 Si8506

Mean

Si8505 Si8524 Si8401 Si8501 Si8603 Si8506

Mean b

36.67 49.57 35.80 34.03 41.00 33.63

38.45 b

37.80 50.53 23.37 44.73 43.23 38.03

39.61 bc

47.23 49.32 23.47 55.77 45.87 35.87

42.92 b

45.07 58.60 36.29 29.39 50.53 48.90

45.13 b

1987

1988

45.62 50.23 33.67 43.57 24.07 31.13

38.21 b

45.96 52.53 20.96 29.17 40.15 29.50

36.38 c

55.47 66.23 54.17 48.27 55.55 40.07

53.29 a

50.41 61.3 47.59 58.77 56.83 51.27

54.36 a

46.49 ab 53.84 a 36.78 b 45.41 ab 41.62 b 35.17 b

45.31 b 55.74 a 32.05 c 40.51 bc 47.68 ab 41.92 b

a Av of 10 leaves inoculated. b Overall means for isolates and cultivars followed by the same letter do not differ significantly by DMRT (P=0.05).

Resistance to 2 diseases in Faizabad, UP, India.

Entries a (%)

Resistant b Moderately Susceptible Probable susceptible escapes

False smut 42.99 23.98 6.79 26.24 Narrow brown 65.67 3.43 13.74 17.16

Disease

leaf spot

a Based on 221 genotypes tested against FS, 231 tested against NBLS. b Reaction: 0 = probable escape, 1-3 = resistant, 4-6 = moderately susceptible, 7-9 = susceptible.

Sources of resistance to rice RYD source plants and confined on

yellow dwarf and its vector healthy rice plants for 30 d to complete the latent period. Twenty 7-d-old test

G. N. Rao and P. Narayanasamy, Plant Pathology Department, Tamil Nadu Agricultural University, Coimbatore 641003, India

We tested 24 rice genotypes for resistance to rice yellow dwarf (RYD) and its green leafhopper (GLH) vector ( Nephotettix virescens Distant).

First- and second-instar GLH nymphs were allowed 48 h acquisition feeding on

seedlings of each genotype were placed individually in test tubes, and inoculated with 2 GLH/tube for 24 h. Inoculated seedlings were planted in earthen pots and disease symptoms monitored.

The genotypes also were tested for reaction to GLH (TN1 and PTB33 were susceptible and resistant checks) using 15 seedlings/ variety in seedbox screening (4-5 second- and third-instar nymphs/seedling).

Sources of resistance to RYD and GLH.

RYD Mean Increase

Genotype infection Reaction a incubation over (%) GLH

(%) period (d) susceptib1e Grade Reaction b

check

IR64 IET7492 IR6 2 TNAU 80030 Tadukan TNAU 831520 IR58 IR30 IR8

IR26 IR5 TNAU 831521 NLR 139-69 IR24 TNAU 80058 ADT 31 TKM 9 AD 85002 TNAU 80042 CO 43 Ponni White Ponni IR20 TN1 (susceptible check) PTB33 (resistant check)

RP1931-54

LSD (P=0.05)

5.0 5.0

10.0 15.0 15.0 15.0 15.0 15.0 15.0 20.0 20.0 20.0 20.0 25.0 25.0 25.0 30.0 30.0 35.0 40.0 40.0 45.0 50.0 70.0 85.0 – –

R R R R R R R R R R R R R R R R R R I I I I I S S – –

40.0 39.0 39.5 35.0 34.7 34.0 33.7 33.3 33.3 33.5 33.0 32.5 32.0 33.0 32.4 31.6 31.5 31.5 31.3 30.5 30.5 30.5 30.0 28.9 27.9

–

0.6

43.4 39.8 41.6 25.4 23.4 21.9 20.8 19.4 19.4 20.1 18.3 16.5 14.7 18.3 16.1 13.3 12.9 12.9 12.2 9.3 9.3 9.3 7.5 3.6 – –

3 R 3 R 3 R 3 R 3 R 3 R 3 R 3 R 5 MR 3 R 5 MR 5 MR 5 MR 5 MR 3 R 3 R 5 MR 5 MR 5 MR 5 MR 7 S 7 S 7 S 7 S 9 HS 1 HR

a R = 0.30, I = 31-60%, S = 60% infection. b HR = highly resistant, R = resistant, MR = moderately resistant, S = susceptible, HS = highly susceptible.

Entries maturing in Sep generally escaped FS and those in Oct, NBLS: 37 genotypes escaped both diseases and 71 showed resistance to both (see table). FS pressure starts building in Oct and is highest in varieties that mature in Nov. NBLS pressure starts building in Nov and is highest in varieties that mature in late Nov and Dec.

Resistance (infection range 5-30%) showed in 18 genotypes: IR64, IET7492, and IR62 recorded very low infection (see table). Incubation period was longest in IR64, followed by IR62 and IET7492. Twenty genotypes were moderately resistant or resistant to vector GLH.

IR62, IR64, and IET7492, with resistance to both RYD and GLH and with long incubation periods, are good donors for developing RYD-resistant cultivars.

Technique to preserve conidia of rice blast (Bl) fungus

Sun Guochang and Sun Shuyuan, Plant Protection Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou; and Shen Zongtan, Agronomy Department, Zhejiang Agricultural University, Hangzhou, China

We studied the effect of preservation conditions on viability and pathogenicity of conidia of four rice Bl fungus Pyricularia oryzae Cav. races.

washed from barley grains with distilled water. The spore suspension was passed through a general filter paper (f 12 cm) in a funnel, dried at 30-35 °C, and stored in an aluminum box (f 10 × H15 cm) at ambient temperature (–4-35 °C) and in a desiccator at three temperatures: ambient, 4 °C, and -20 °C.

Conidia viability was evaluated every 3-4 mo in a drop of distilled water on a concave slide incubated at 28 °C for 24 h. Pathogenicity was tested by

Freshly produced conidia were

IRRN 14:4 (August 1989) 17

Effect of preservation conditions on Pyricularia oryzae conidia viability, Hangzhou, China, 1986-88. (1) Stored in aluminum box at ambient temperature, (2) stored in a desiccator at ambient temperature, (3) stored in a desiccator at 4 °C, (4) stored in a desiccator at –20 °C.

inoculating 11 indica and japonica rice varieties.

Conidia stored for 4 mo in an aluminum box at ambient temperature died. Conidia stored for 4 mo in a desiccator retained their original level of viability; viability did not differ significantly with temperature. Viability of conidia stored in a desiccator for 9.5 mo varied significantly with temperature and fungal race (see figure). Except that fungal race ZA 63 changed to race ZA 61 after 9.5 mo, conidia retained their original level of pathogenicity. When spores are stored in a desiccator at -20 °C, it is not necessary to synchronize fungus sporulation with seedling growth for artificial inoculation.

Methods for evaluating resistance to Pyricularia oryzae in rice

A. S. Prabhu, National Research Center for Rice and Beans (EMBRAPA-CNPAF), Caixa Postal 179, 74000 Goiânia-GO, Brazil

We tested three methods for assessing partial resistance to blast (Bl) in rice. Partial resistance is used to mean incomplete or intermediate resistance, without any genetic connotation.

Seven Brazilian land races and one exotic cultivar were evaluated. Widely grown commercial IAC47 and introduced IRAT13 were included as susceptible and resistant checks.

Disease severities obtained through artificial inoculation with a race virulent

18 IRRN 14:4 (August 1989)

on all genotypes were compared with mobile nursery tests and the uniform Bl nursery (UBN).

mobile nursery test, entries were sown in plastic trays (22 × 33 × 12 cm) containing soil fertilized with NPK + Zn and raised in the glasshouse. Each tray contained 10 randomly distributed genotypes sown one row each and thinned to 10 plants/row. Each method had three replications.

For the inoculation test, seedlings were inoculated at the fourth leaf stage with an aqueous spore suspension (2.5 × 10 5 spores/ml) of race IB-1, using De Vilbiss nozzle no. 15 attached to an air compressor. Inoculated seedlings were incubated at 100% relative humidity for 24 h and then transferred to the

For the inoculation test and the

The International Hybrid Rice Newsletter is published for researchers in hybrid rice development and technology. Its content focuses on discussions of current issues; it does not publish research reports. For more information, write Dr. S. S. Virmani. Hybrid Rice Newsletter editor, IRRI, P. O. Box 933, Manila, Philippines.

glasshouse. For the mobile nursery test, healthy

seedlings at the fourth-leaf stage were exposed to natural inoculum by placing the trays adjacent to the heavily infected UBN for 48 h. They were incubated 24 h in moist chamber then transferred to the glasshouse.

The mobile nursery test was conducted when leaf Bl reached maximum severity in the genotypes being tested in the UBN. Average night/day temperatures during the experimental period were 21 / 29 °C ± 2 °C.

Plants in the inoculation test and mobile nursery were assessed separately and rated 0.25, 0.5, 0.75, and 1.0 for disease severity and color and type of susceptible lesion. Disease severities

were based on 10 plants/genotype. Overall disease severities were considered to sum the effect of partial resistance components.

In the UBN, one row of each genotype was sown, with three replications. Disease severities were measured by using 0-9 scale ( Standard evaluation system for rice ).

The disease severities in the artificial inoculation test and the mobile nursery method indicated differences in partial resistance (see table). Because of high disease pressure in the UBN, fewer differences were found among the test genotypes.

used to identify levels of partial resistance to P. oryzae in advanced breeding lines.

The mobile nursery method could be

Insect resistance

Effect of rice gall midge (GM) resistance on parasitic behavior of Platygaster oryzae Cameron

M. Muthuswami and K. Gunathilagaraj, Agricultural Entomology Department, Tamil Nadu Agricultural University, Madurai 625104, India

We studied the influence of GM resistance in rice on the parasitic activity of the GM parasite Platygaster oryzae Cameron during Oct 1987. Twenty rice accessions with different levels of GM resistance were raised in the field in 1-m rows, spaced 15 cm between hills and 20 cm between rows. GM incidence was recorded 30 and 50 d after transplanting. Parasitization was taken as the percentage of parasitized galls in each accession.

Five parasitized and five unemerged galls from each accession were collected and held in test tubes with water. Emerging adults were counted. Parasitization of rice GM ranged from 9.04 to 100%. The correlation between incidence of rice GM and its parasite

Leaf Bl severity differences in 3 methods of screening. a Goiânia, Brazil.

Genotype Inoculation with Mobile Uniform

virulent race IB-1 (MDS) b

nursery blast nursery (MDS) (av. score) c

Ferrinho 0.78 a 0.74 ab 8.3 a Oitentão 0.71 a 0.85 a 6.0 d Cam Roxa 0.67 a 0.57 bcd 6.0 d Pedregulho 0.63 ab 0.61 abc 7.0 bc Paga Divida 0.62 ab 0.71 ab 6.0 d IAC 47 0.43 bc 0.43 cde 7.0 bc IRAT104 0.39 c 0.12 f 6.0 d Chatão 0.37 c 0 6.6 cd Arroz de Guerra 0.33 c 0.31 ef 7.6 ab IRAT13 0.31 c 0.36 de 7.3 bc

a In a column, means followed by the same letter are not significantly different at the 5% level by Tukey test. b Mean disease severity, av of 3 replications. 0 = highly resistant, 1 = highly susceptible. Severity values grouped into 0.25, 0.50, 0.75, and 1.0. Two types of susceptible lesions, type I and type II, were scored 0.25 and 1.0, respectively. Type I = restricted isolated susceptible lesion types

ranging from white to grey, spindle shaped to irregular, rapidly coalesce. The infection coefficient with reddish brown margin, rarely coalesce. Type II = lesions with water soaked appearance, color

multiplied with disease score for lesion type with severity values will give a maximum disease rating of 0.25 to lesion type I. c Standard evaluation system for rice 0-9 scale, av of 3 replications.

Correlation a between GM and its parasite in rices with different resistance levels.

GM

(%) (no.)

Damage Parasitization Adults that emerged Accession incidence score (%)

RP1579-4-6-1 RP2362-110-40-1 IET9556

IET9690

IET9700

RP2432-105-7-1

RP2199-41-25-34-55

RP2199-3-3-1-1 RP2431-11-14-3 RP2311-276-71 TKM4 CO 27 CO 12 ASD9 TKM1 IR60 TNAU831520 CO 35 IR20 IR30

1.81 3.63 3.63 3.63 5.35 5.55 8.77 9.09

14.81 14.81 18.18 27.27 30.90 38.18 48.21 63.63 81.48 94.54 96.42 98.18

3 3 3 3 3 5 5 5 5 5 7 7 7 7 7 9 9 9 9 9

100.00 50.00 50.00 66.66 25.00 40.00 66.66 40.00 37.50 50.00 22.22 40.00 32.00 45.76 33.82 32.43 9.04

26.79 10.00 28.71

17 26 16 25 31 30 42 42 39 42 41 46 44 43 46 49 45 47 44 45

a r = (-0.627)**, Y = 52.923 + (-0.377) X.

was negative. Resistant accession RP1579-4-6-1 had 1.81% GM incidence and 100% parasitization. TNAU831520 had 81.5% GM incidence and only 9.04% parasitization (see table). Adult parasites emerging from a single gall ranged from 16 to 47. In general, adult emergence was low from resistant rice accessions.

For information on ordering IRRI publications, write Communication and Publications Dept., Div. R, IRRI, P.O. Box 933, Manila, Philippines.

IRRN 14:4 (August 1989) 19

Drought resistance

Screening advanced breeding lines and germplasm for drought resistance under upland conditions

S. Pramanik and S. Gupta, Zonal Adaptive Research Station, Krishnagar, Nadia (W.B.), India

We screened 180 germplasm and advanced breeding lines involving parents of indica-japonica types under direct-seeded upland conditions at Krishnagar (gangetic alluvial zone) during the summer season (May-Jun). Short-duration lines are preferred for this season, since the monsoon generally appears about the third week of Jun. Short duration also gives room for the subsequent wet season crop.

Soil of the experimental plot had light medium texture with moderate sloping (susceptible to erosion). Soil had pH 7.2

Some characteristics of 11 entries screened under upland direct seeded situations. Krishnagar, India.

Panicle length Wt of Height

Days to (cm) Grain single

Sheath

(cm) flowering Mean SD

type a (g)

panicle blight score

Designation 50%

IR47701-79-B-14 IR47701-79-B-1 Milyang CNA4196 IAC165 CNA4746 CNA4125 GS529 Dular (check) IET2223 (check) Rasi (check)

94 93 91

101 107 104

79 110

99 93 92

75 73 67 72 76 68 71 67 67 75 73

20.0 24.6 15.0 18.5 21.0 20.5 22.2 23.0 19.5 23.0 20.5

1.36 2.16 1.25 1.26

(0.16) 1.32 1.96 1.21 2.31 1.27 1.81

MS MS SB LS MS LS LB LS MS MS LB

2.5 2.8 3.3 3.7 3.7 2.8 1.8 4.2 2.8 4.2 3.0

0 0 3 5 0 5 5 1 7 1 6

a MS = medium slender, SB = short bold, LS = long slender, LB = long bold.

and is deficient in N, organic matter, and phosphate. The crop was subjected to moisture stress at different growth stages, particularly during the seedling stage.

The experiment was laid out as a simple observational plot, with two 2-m rows/line (direct seeded), with 20 cm between rows.

Eight promising lines were identified

(see table). GS529 and Milyang have the same number of days to flowering as Dular, but GS529 has longer panicles and long slender grains, and is resistant to sheath blight. Panicle weight is high. Advanced breeding line RP47701-79-B- 1, with 73 d to flowering and high resistance to sheath blight, is considered promising.

Excess water tolerance

Promising breeding lines for submergence-prone and medium-deep rainfed lowland conditions

S. K. Sinha, Rice Research Station, Chinsurah, Hooghly, West Bengal, India; and D. J. Mackill, B. N. Singh, and M. M. Amante, Plant Breeding Department, IRRI

We evaluated 209 rice breeding lines and local and improved cultivars under two water regimes in the field at IRRI. Cultivars for both trials were sown 27 Jun and transplanted 27 Jul 1988.

In trial 1, entries were submerged gradually to a 60-cm water level 45 d after sowing (DAS). Water depth was maintained for 12 d, then gradually brought down to 25 cm for the remainder of the season. In trial 2, entries were submerged suddenly to 60

20 IRRN 14:4 (August 1989)

cm at 50 DAS, water depth was maintained for 8 d, then brought down to less than 10 cm.

were measured (tip of the longest leaf) Plant height before and after flooding

and percent survival calculated. Elongation was calculated as the difference in height before and after flooding.

Survival was 24.9% for trial 1 and 36.7% for trial 2. In trial 1, the correlation between survival and initial plant height was low, but significant ( r

Entries with the highest survival in 2 field tests of performance a under submergence. IRRI, 1988 wet season.

Breeding line Survival (%) Elongation (cm)

Submergence Mature Days to Trial 1 Trial 2 Trial 1 Trial 2 tolerance b height c

maturity a (cm)

IR49830-26-1-2-1 IR51052-2-3-1-6 IR6370-K23-1 IR51053-10-2-3-2 IR49830-29-1-3-3-2 IR43470-7-3-5-1 BKNFR76106-16 (R ck) IR43522-37-3-3-3 IR42 (susceptible check)

65 70 85 59 58 54 11 55

0

75 68 58 68 65 58 89 43 0

29 – – – 12 25 17 27 –

19 – –

15 5

19 20

–

–

3.0 9.0 9.0 8.0 1.0 3.0 6.6 8.2 8.5

130 140 120 140 140 115 105 140 105

140 135 SEN 130 130 130 120 SEN 135

a Trial 1 = slow submergence, trial 2 = rapid submergence. b Average scores from screenhouse screen-

sensitive. ing in tanks, compared with tolerant check FR13A. c Average of field data. d SEN = photoperiod

We compared the salt tolerance of hybrid NIAB-Rice-1 and mutants NIAB-Rice-3, RST-24, and BSRS-l-85 (derivatives of Basmati 370) with that of their parents Jhona 349 and Basmati 370.

Z. Aslam, M. S. Sajjad, M. Mujtaba, M. A. Awan, and K. A. Malik, Nuclear Institute for Agriculture and Biology, Faisalabad, Pakistan

= 0.30); the correlation of survival and elongation was highly significant ( r = 0.71). Many tall plant types were able to escape flood through elongation.

In trial 2, the correlation of survival and initial plant height also was low ( r = 0.31); survival was not correlated significantly with elongation ( r = -0.20). Because tall types lack submergence

tolerance, they were unable to survive sudden inundation.

Many entries that performed well in one trial did poorly in the other (see table). Most of the entries with the best overall survival have shorter plant height, indicating that they survive from tolerance for submergence, not from

escape.

29 derive their submergence tolerance from the traditional cultivar FR13A. They have shown very high submergence tolerance in greenhouse screening at IRRI and have a very good plant type.

IR43470-7, IR49830-26, and IR49830-

Adverse temperature tolerance

Screening rice seedlings for cold tolerance

M. Maheswaran and M. Subramanian, Agricultural Botany Department, Agricultural College and Research Institute, Madurai, Tamil Nadu, India

We screened 20 elite rice cultivars for cold tolerance at the seedling stage during 1988-89.

Uniform seeds, 50/entry with 2 replications, were soaked in water 24 h, washed repeatedly in distilled water, covered with moist tissue paper, and incubated at room temperature. After 3 d incubation, the seeds were transferred to glass containers with 3 cm water and kept at 4 °C. After 10 d of low temperature treatment, the containers were transferred to room temperature for 1 d.

Differences in seedling survival at low temperature were not significant. Based on seedling height, 16 entries showed tolerance for cold stress (see table).

Cold tolerance at early seedling stage of IET entries, based on seedling survival and seedling height. Tamil Nadu, India.

Entry Seedling Seedling Shoot/ Cold survival height root tolerance

(%) (m) ratio score b

IET 6786 IET 7261 IET 7589 IET 7946 IET 7988

IET 7989 IET 8024 IET 8101 IET 8626 IET 8866 IET 9202 IET 9315 IET 9797 IET 9802 IET 9815 IET 10358 IET 10385 IET 10505 IR46 MDU2 (control)

54 76 56 78 50

50 76 78 58 81 79 62 57 58 64 56 70 69 60 66

8.0 10.2 13.3 10.3 13.1 14.3 13.8 12.0 8.9

11.4 13.2 12.3 9.3

12.8 11.0 12.7 12.7 12.7 11.7

8.0

0.9 0.7 0.7 0.6 0.9

0.9 0.8 1.1 0.7 1.3 0.8 0.9 0.5 0.9 0.7 0.8 0.8 0.8 1.1 0.5

3 1 1 1 1 1 1 1 3 1 1 1 3 1 1 1 1 1 1 3

a 1 = all seedlings with green leaves, 3 = less than 30% of seedlings dead, 5 = 30-50% of seedlings dead, 7 = more than 50% seedlings dead, 9 = all seedlings dead. b 1 = seedling height more than 10 cm, 3 = seedling height 8-10 cm, 5 = seedling height 5-7 cm, 7 = seedling height 3-4 cm, 9 = seedling height less than 1 cm.

Adverse soils tolerance

Effect of increased salinity on rice genotypes

Seedlings grown on a nonsaline field were transplanted at 45 d after sowing in concrete tanks (254 × 82 × 23 cm) filled with quartz gravel saturated with Hoagland nutrient solution. One seedling/ hill per genotype was transplanted at 30- × 30-cm spacing. The experiment was in a randomized block design with six replications. Root zone EC levels of 2.4, 5.0, and 10.0

IRRN 14:4 (August 1989) 21

8% silt, and 2% clay. Fertilizer was 60- 60 PK/ha at planting and 100 kg N/ha, half at tillering and half at panicle initiation.

Overall, yields were poor, from 1.8 t/ha for IRAT104 to 0.3 t/ha for OS6 (Table 1). IRAT104 and IRAT161 significantly outyielded local check

False

Influence of increased salinity on yield per plant of rice genotypes. Faisalabad, Pakistan.

Name of mutant or hybrid

Yield (g/plant) Regression equation

LD 50 (EC associated with 50% reduction over

minimum salinity)

NIAB-Rice-1 45.5 36.5 22.0 Y = 52.4515-3.0164 X Jhona 349 44.8 16.5 Y = 51.3326-3.5918 X 8.1

9.7 30.2

NIAB-Rice-3 26.3 23.5 6.0 Y = 34.7366-2.7822 X 7.7

2.4 dS/m 5.0 dS/m 10.0 dS/m

(RST-24) BSRS-1-85 24.0 20.8 5.3 Y = 31.4682-2.5462 X Basmati 370 23.7 15.7 3.9 Y = 29.3532-2.5724 X 6.8

7.7

dS/m were imposed 1 wk after transplanting, using NaCl in ratio of 4:10:5:1. EC levels were checked daily and maintained at desired levels.

from the regression equation between salinity level and yield/plant.

NIAB-Rice-1 was the most salt tolerant (see table).

Salt tolerance was estimated as LD 50

Integrated germplasm improvement

Rajshree, a new rice variety for rainfed lowlands in Bihar, India

B. N. Singh, S. P. Sahu, R. Thakur, and Y. Prasad, Rajendra Agricultural University, Pusa 848125; and S. Saran, Agricultural Research Institute, Mithapur, Patna 800001, India

TCA80-4 (1ET7970) has been released as Rajshree for cultivation in rainfed lowland areas of Bihar. The photoperiod-insensitive mutant from a land race collection from Bhagalpur District will substitute for Mahsuri,

BR8, and other local varieties suitable for up to 25-cm water depth. When transplanted early, Rajshree can tolerate deeper water.

Rajshree yielded higher than checks at Pusa and Patna (Table 1). It has intermediate height (130 cm) and matures in 145 d. It is resistant to bacterial blight, brown spot, sheath rot, false smut, and rice tungro virus (Table 2). It showed relatively better tolerance for drought at vegetative and reproductive stages than Mahsuri in farmers’ field trials. With late sowing, it yields better than Mahsuri and has less yield reduction when 60-d-old seedlings

Table 1. Yield of Rajshree (TCA80-4) in trials at Pusa and Patna, India.

Yield (t/ha)

Variety 1981 1982 1983 1984 1985 a Mean

Pusa Pusa Patna Pusa Patna Pusa Patna Pusa Patna b Patna c

TCA80-4 2.7 2.4 3.1 3.5 3.4 2.4 2.2 1.0 3.0 3.1 2.7 BR8 1.6 2.5 2.9 2.5 2.9 2.9 2.7 1.1 2.7 2.6 2.4 Mahsuri na 2.3 2.8 3.2 3.8 2.3 2.2 0.4 2.4 2.8 2.5 LSD 0.05 0.7 0.9 1.5 0.6 0.7 0.3 0.7 0.1 0.2 0.2 CV (%) 22.9 19.8 27.2 15.0 12.0 6.9 17.2 44.9 4.0 8.4

aWater depth was 80 cm in Pusa, and 50 cm in Patna. bBelkunda Chaur. cMikki Chaur.

Table 2. Reaction of Rajshree (TCA80-4) to rice diseases.

are transplanted.

mm, breadth 2.0 mm, L/ B ratio 2.9); 1,000-grain weight is 19 g. Its husk is straw colored and grains are nonchalky. Head rice recovery and cooking and eating quality are better than those of Mahsuri.

In 553 minikit tests in Bihar State 1984-86, average yield was 2.38 t/ha; maximum yield was 4.4 t/ ha in Patna District and 5.8 t/ ha in a farmer’s field in West Champaran District during 1986 wet season.

Grain is medium slender (length 5.8

Evaluation of upland rice lines at Morogoro, Tanzania

S. O. W. M. Reuben and S. D. Katuli, Crop Science Department, Sokoine University of Agriculture, P.O. Box 3005, Morogoro, Tanzania

We evaluated 12 upland rice lines from various research centers. Each line was direct sown at 20- × 20-cm spacing in the field under rainfed conditions during the 1987 cropping season, in a randomized complete block design with three replications.

Soil was sandy, with pH 6.4, 2.6% organic matter, and 0.16% total N. Particle size distribution was 90% sand.

SES a score (0-9 scale)

Variety Tungro b Brown Bacterial Sheath spot blight rot smut

TCA80-4 3 3 3 3 3 BR8 7 5 7 3 Mahsuri 9 5 7 5 7

a Standard evaluation system for rice. b Based on natural incidence in 1980 wet season at Pusa.

5

22 IRRN 14:4 (August 1989)

Table 1. Means for the variables studied and total rainfall for each rice line during the 1987 cropping season at Morogoro, Tanzania. a

Total Cultivar rainfall

Duration Yield (d) (t/ha)

Plant Mean Tillers/ Harvest Filled Drought

(mm) (cm) length (cm) (no.) (%) panicle (%) score (0-7) height panicle plant index grains/ effect

Farox 229 297.4 140.0 abc 0.9 bc 73.0 cd 15.1 d 5.0 b 26.0 ab 44.0 b IRAT104 297.1 135.0 d 1.8 a 78.3 bc 17.8 ab 6.0 ab 46.0 a 65.0 ab IRAT156 297.4 139.3 bc 0.8 bc 76.0 bcd 18.4 ab 6.0 ab 48.0 a

297.1 89.0 a

IRAT161 129.3 e 1.3 b 78.3 bc 16.8 bcd 8.0 a 31.0 ab 63.0 ab IRAT170 293.8 126.7 f 0.4 cd 66.3 de 15.7 cd 7.0 ab 31.0 ab 50.0 ab ISA6 297.4 138.7 c 0.9 bc 70.0 cd 19.3 a ITA128 297.1 135.0 d

6.7 ab 31.0 ab 60.0 ab 0.8 bc 68.0 cde 17.2 bc

ITA235 293.8 124.0 f 0.7 bc 7.3 ab 26.0 ab 51.0 ab

76.0 bcd ITA305 298.3 125.3 f

18.6 ab 8.0 a 0.8 bc

28.0 ab 56.0 ab

ITA315 58.0 e 15.5 cd 6.7 ab 43.0 ab 53.0 ab

293.8 122.3 g 0.4 cd OS6 297.1

68.3 cde 16.9 bcd 138.0 c 0.3 d 84.7 ab 16.7 bcd 5.3 b 26.0 ab 46.0 ab

8.3 a 17.0 b 51.0 ab

297.8 Supa X

146.7 a 0.4 cd 93.3 a 18.6 ab 133.4

7.0 ab 19.0 b 41.0 b

SX 17.2 6.8 31.0

0.7 0.18 3.4 8.0 7.3 56.0

CV (%) 0.6

0.9 0.7

38.5 7.7 6.1 17.9 17.7 23.2

0.80 74.2

a In a column, mean values followed by the same letter do not differ significantly (P<0.05) by DMRT.

1.8 b 1.7 b 1.7 b 2.0 b 2.7 a 2.0 b 2.2 ab 1.8 b 2.2 ab 1.8 b 2.4 ab 2.7 a 2.1 0.2

16.8

Table 2. Simple correlation coefficients between the variables studied in the upland rice lines at Morogoto, Tanzania, 1987 season. a

Variable 1 2 3 4 5 6 7 8 9 10 11 12

1. Drought effect – 2. Days to –0.127

3. Plant height 0.176 0.612* – 4. Panicle length –0.169 0.514 0.451 – 5. Tillers/plant 0.067 0.444 –0.169 0.253 6. Panicle weight –0.570* –0.029 0.039 0.261 0.095 7. Filled grains/ –0.637 –0.024 –0.152 0.407 0.123 0.872**

panicle (%) 8. Harvest index –0.406 0.015 –0.274 0.036 –0.352 0.669* 0.745** 9. Panicles/m 2 0.238 –0.498 –0.273 0.235 0.629* –0.111

10. 1000-grain weight 0.243 –0.192 –0.173 –0.703* –0.371 –0.274 –0.359 –0.075 –0.198 11. Plants/m 2 0.228 –0.280 –0.373 0.301 0.604* 0.088 0.233

–0.608* 0.099 –0.029 –0.125 0.097 0.808** 0.672* 0.599* –0.163 12. Grain yield 0.126 0.131 –

maturity –

– –

–

– 0.036 –0.277 –

– 0.004 0.722** –0.139

Significance of regression on yield b (-ve)* (+ve)* (+ve)*

a *, ** denote significance at P<0.05 and 0.01, respectively. b Multiple regression when all the variables were included in the equation.

Supa. The low yields were attributed to then, we provided two supplemental Panicle weight, filled grains/panicle, drought, particularly during the furrow irrigations a week. harvest index, and yield were positively reproductive stage, between booting and Panicle weight and harvest index had associated. grain filling. After two rainless weeks positive effects on seed yield (Table 2).

Yield potential of IR7167-33- 2-3 and Tainan V at Ndop Plain, Northwest Cameroon

M. P. Jones, D. Janakiram, A. C. Roy, and F. Jeutong, IRA/NCRE/USAID/IITA rice project, Dschang, Cameroon; and S. B. C. Wanki, UNVDA, Ndop, Northwest Province, Cameroon

Rice, a relatively new crop in Cameroon, is grown on about 20,000 ha

of irrigated lands. Ndop Plain at an altitude of 1,200 m above sea level in the Northwest Province is one of the three major rice production areas. The primary constraints to increased productivity are low temperature and associated severity of sheath rot (ShR) and grain discoloration (GlD).

Tainan V, a popular traditional variety, has bold, short, chalky grains and poor keeping quality. IR7167-33-2-3 was released for general cultivation in

1987. It has medium-long, less chalky grains, and fair keeping quality. It yields higher than Tainan V, is low temperature tolerant, and resistant to ShR and G1D. It is also 8 d shorter in duration.

We examined the yield potential of the two varieties over several seasons from on-station and farmers' field trials. The on-station yield trials used early transplanting at 25- × 20-cm spacing, 2- 3 seedlings/hill, and 60-40-40 kg

IRRN 14:4 (August 1989) 23

Table 1. Performance of IR7167-33-2-3 and Tainan V in research station observational yield trials. Cameroon, 1987 and 1988.

Grain yield a Reaction b to Variety or line (t/ha) Duration

(d) Sheath Grain exsertion b Panicle

1987 1988 rot discoloration

Tainan V 4.3 3.3 150 5 5 3 IR7167-33-2-3 5.5 4.4 142 3 3 3

a Mean of 6 trials/year. b Standard evaluation system for rice 0-9 scale.

Table 2. Yields of IR7167-33-2-3 and Tainan V in farmers’ fields at Ndop Plain, Cameroon.

Grain yield a (t/ha)

1987 1988

Tainan V 3.4 3.2

Variety or line

IR7167-33-2-3 4.9 4.5

a Mean of 6 farms sampled/year.

NPK/ha. The farmers’ field trials were station trials, IR7167-33-2-3 outyielded V on all six farms sampled in 1987 conducted according to normal farmer Tainan V by an average 36%. IR7167- (Table 2). Yield trends were similar in practices. 33-2-3 also showed greater resistance to 1988.

IR7167-33-2-3 outyielded Tainan V in ShR and GlD. IR7167-33-2-3 has an average yield 1987 and 1988 trials at the Bamunka In farmers’ fields in the Bamunka advantage over Tainan V of 32% on research site (Table 1). In 1988 on- area, IR7167-33-2-3 outyielded Tainan station and 45% in farmers’ fields.

ASD17, a short-duration red rice variety for tail end irrigation areas of Tambiraparani Delta and Kanyakumari District, Tamil Nadu

M. Rangaswamy, K. Mohanasundaram, P. Shanmugasundaram, M. Subramanian, S. Palanisamy, W. W. Manuel, T. Sundaram, S. Vairavan, K. Ganesan, and A. Ithayarajan, Rice Research Station, Ambasamudram, Tamil Nadu, India

Short-duration red rice culture AS688, isolated from the double cross derivative of ADT31/Ratna//ASD8/IR8, has been released as rice variety ASD17 for

cultivation in tail end irrigation areas of Tambiraparani tract and Kanyakumari District. It is suitable for cultivation during kannipoo season (Apr-Jul) in Kanyakumari and kar season (Jun-Sep) and late pishanam season (Nov-Feb) in Nellai Kattabomman District. ASD17 can replace local varieties Kuruvai, Arupatham kuruvai, and Annapoorna in Kanyakumari and Thuyamalli in Nellai Kattabomman.

100 d. Mean grain yield was 5.4 t/ha over 10 yr in 27 different trials (see table). Mean straw yield was 9.0 t/ha.

Early senescence is its distinguishing character. The variety produces its maximum grain yield when younger

ASD17 is 96 cm tall and matures in

Performance of ASD17 in Tamil Nadu.

Trials

(no.) TKM9 ASD8 Cauvery Arupatham Anna- kuruvai poorna

% increase Trial

Rice Research Station, Ambasamudram, 27 6.8 – – – –

Adaptive Research Trials, Kanyakumari 1979-88

District, 1981 wet season 10 2.6 1981 semidry season 7 6.1 1984 and 1987 1988

District, 1987 and 1988

Project, 1981 direct seeded rainfed

Project, 1981 direct seeded irrigated

Project, 1981 transplanted

– – – –

– – – –

15 – 20 – –

– – 1.8 –

Adaptive Research Trials, Tirunelveli 34 – 37.3 – – –

All India Coordinated Rice Improvement 9 – – 7.7 – –

All India Coordinated Rice Improvement 2 – – 1.7 – –

All India Coordinated Rice Improvement 9 – – 10.1 – –

– – 7.4

seedlings (18-20 d) are transplanted. Grain is short and bold red rice, with high consumer preference.

and blast and moderate resistance to brown planthopper and sheath rot.

ASD17 has field tolerance for tungro

Performance of some improved rice varieties under irrigated and rainfed lowland conditions at Parwanipur, Nepal

M. N. Paudel, National Rice Improvement Program (NRIP), Parwanipur, Nepal

We studied yield and yield attributes and some agronomic traits of 10 released and 1 prerelease variety under irrigated and rainfed lowland conditions in 1988 wet season (May-Oct).

The experiments were laid out in a randomized complete block design with three replications. Seeds were sown on dry seedbed on 26 May for irrigated rice and 7 Jun for rainfed lowland. Seedlings were transplanted at 1 seedling/hill, 25- × 25cm row spacing, 30 d after sowing. Fertilizer was applied at 80-20-20 kg NPK/ha. Plots were protected against weeds, insect pests, and diseases. Net area harvested was 5.0 m 2 /plot.

Filled grains were separated from unfilled grains using Dockaging

24 IRRN 14:4 (August 1989)

Table 1. Pooled analysis of yield components of 11 rice varieties under irrigated (I) and rainfed lowland (R) conditions at Parwanipur, Nepal, 1988 wet season.

Productive tillers at Filled grains/panicle harvest (no.) (no.) % unfilled grains/panicle a 100-grain weight (g)

I R Mean I R Mean I R Mean I R Mean Variety

NR15016-2-4-1-3 31.3 38.4 34.9 247.27 258.6 252.93 1.93 CH45 47.7 66.7 57.2 73.0 62.6 67.8 2.51 Makawapur 1 39.0 52.7 45.8 119.54 124.6 122.07 2.55 Barkhe 2 48.0 65.0 55.5 104.07 119.0 115.53 1.86 Sabitri 45.0 57.0 51.0 120.34 125.2 122.77 2.02 Bindeswari 46.0 62.0 54.0 95.07 120.4 107.33 1.95

Ghaiya 2 41.3 51.7 46.5 97.17 110.6 103.87 2.28 Chaite 4 55.3 51.3 53.3 60.87 88.4 74.63 2.32 Masuli 42.7 54.7 48.7 140.47 176.8 158.63 1.59 Janaki 32.0 47.4 39.7 87.07 143.0 115.0 2.58

Mean 42.1 54.7 48.0 115.28 133.69 124.0 2.14 F test b ** * CV (%) 15.1 14.1 14.6 21.11 14.07 17.39 5.88 LSD (0.05) 4.4 5.3 2.4 16.91 13.07 7.5 0.27 Cultural type × genotype – – ns – – ns ns

Mallika 35.0 55.3 45.2 123.34 141.0 132.17 2.05

** ** ** ** **

a Figures in parentheses are transformed values and LSD values refer to them. b ** = significant at 0.01 probability, * = significant at 0.05 probability, ns = not significant.

11.04 (3.28) 4.68 (2.27) 8.58 (3.01) 9.26 (3.03) 7.97 (2.89)

15.05 (3.91) 18.28 (4.32)

9.71 (3.16) 21.89 (4.57)

9.23 (3.04) 8.37 (2.92)

11.28 (3.31) ns

23.69 – –

6.59 (2.65) 7.31 (2.78) 7.22 (2.76) 5.88 (2.51) 8.63 (3.01) 5.9 (2.51) 6.04 (2.51) 4.3 (2.17)

11.25 (3.38) 5.71 (2.48) 6.9 (2.69)

6.88 (2.68) *

12.34 0.22

–

8.81 (2.96) 5.99 (2.52) 7.9 (2.92) 7.57 (2.72) 8.3 (2.95)

10.47 (3.21) 12.16 (3.46)

7.0 (2.66) 16.57 (3.97)

7.47 (2.76) 7.63 (2.8)

9.08 (2.99) *

20.12 0.2

ns

1.95 2.46 2.52 1.77 2.07 1.95 2.0 2.23 2.32 1.55 2.52

2.12

5.78 0.08

**

–

1.92 2.57 2.59 1.96 1.97 1.95 2.1 2.34 2.32 1.64 2.65

2.18

6.15 0.08

**

–

Table 2. Pooled analysis of some agronomic traits of 11 rice varieties under irrigated (I) and rainfed lowland (R) conditions at Puwanipur, Nepal, 1988 wet season.

Plant height (cm) Flowering (d after sowing) Grain yield (t/ha)

I R Mean I R Mean I R Mean Variety

NR15016-24-1-3 CH45 Makawanpur 1 Barkhe 2 Sabitri Bindeswari Mallika Ghaiya 2 Chaite 4 Masuli Janaki

Mean F test a

CV (%) LSD (0.05) Cultural type ×

genotype

141.8 124.73 113.2 100.53 100.26 104.13 125.2

91.93 96.4

134.2 104.06 112.4

** 3.45 2.96

-

142.4 110.6 108.26

88.8 103.4 104.0 120.1

89.9 94.4

127.9 105.0 108.6

** 9.65 7.13 -

142.2 117.66 106.7

94.66 101.83 104.04 122.65

90.91 95.4

131.05 104.53 110.00

7.17 2.73 ns

**

120.33 88.0

126.33 126.33 121.0

96.0 90.33 84.33 88.66

122.0 105.33 106.24

2.72 2.00

**

-

119.0 81.3

122.0 126.3 116.6

94.0 93.0 89.0 85.6

125.3 106.3 105.4

3.5 2.5

**

-

119.66 84.65

124.16 126.31 118.8

95.0 91.66 86.66 87.13

123.65 105.81 213.57

3.12 1.14 ns

**

2.8 2.4 2.0 2.0 1.7 2.5 2.3 2.1 1.8 2.4 1.8 2.2

14.6 0.2

*

-

3.6 2.7 3.2 3.1 2.6 3.0 3.0 3.0 2.5 3.6 2.8 3.0

11.9 0.2

*

-

3.2 2.5 2.6 2.5 2.1 2.8 2.7 2.5 2.2 3.0 2.3 2.6

13.2 0.08 ns

**

a ** = significant at 0.01 probability, * = significant at 0.05 probability, ns = not significant. Correla- tion between number of filled grains/panicle and no. of productive tillers at harvest ( r = –0.749**)

tion between plant height and yield ( r = 0.792**) (n = 11). (n = 11). Correlation between no. of filled grains/panicle and yield ( r = 0.744**) (n = 11). Correla-

Machine. Yield attributes are presented in Table 1 and agronomic attributes in Table 2.

relatively better under rainfed lowland condition than under irrigated. That may be partly because of monocropping in rainfed lowland, with greater availability of micronutrients. This indicates that identification of improved varieties suitable for broad adaptability is possible.

Yield and agronomic components are

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MAU2159, a high-yielding glutinous rice for East China

L. H. Zhu and L. Y. Ding, Agronomy Department, Nanjing Agricultural University (NAU), Nanjing, China

NAU2159, released in 1985, has proven to fit farmer demands for a high-yielding

Comparison of some traits of NAU2159 and its parents (1986).

Days Plant Panicle Spikelets/ Seed 1000- Protein Amylose Alkali Gel con- Cultivar to height length panicle set grain content content spreading sistency

heading (cm) (cm) (no.) (%) wt (g) (%) (%) value (mm)

Nanjing 11 NAU2159 IR29

98.1 101.3 87.4

24.0 24.0 18.9

152.6 166.3

77.8

79.8 82.1 89.2

26.7 27.4 22.8

13.00 a

9.41 c

8.00 b

92 96 96

27.8 a

2.4 c

0.0 b

6.2 a

6.0 c

6.2 b

30 a

103.5 c

99.0 b

a From IRRI, 1982. b From IRRI, 1980. c From Hubei Academy of Agricultural Science, 1986.

IRRN 14:4 (August 1989) 25

Ö X + 0.5

We screened 330 cultivars during 1988 to identify a suitable rice variety for the low-lying marshy areas along the tidal creeks of Andamans. Cultures included

advanced bulk populations, elite lines, and F 1 anther culture derivatives from IRRI.

Seedlings (21-d-old) were transplanted in a field with normal soil and in a screening plot close to the sea (soil EC 6.5 dS/m and pH 4.2). The screening plot was allowed to be fully inundated by 50-60 cm seawater 7 d after transplanting. That water was maintained through the cropping period by bunding the experimental plot. Rainfall totaled 2,930 mm during 1988 cropping season. EC varied from 2 to

6.5 dS/m and pH, from 3.9 to 4.6. In the screening plot, all but 18 advanced bulk populations from IRRI, 6 elite lines from India, and the local check died. The surviving 25 lines are of long duration and short-statured (see table).

Local variety C-14-8, culture 88-038, and culture 88-121 are found to be promising.

cultivar with excellent palatability and resistance to bacterial blight and blast.

NAU2159 was developed from a cross between Nanjing 11, a popular local variety, in Jiangsu Province, and IR29, a donor of disease resistance and waxy endosperm.

In 4 yr demonstration (1985-88) along

the lower and middle reaches of the Yangtze River Valley, yields were 7-9 t/ha, 7.5 t/ha average. NAU2159 matures early (duration 130-135 d) and is adapted to the areas flanked by 29- 34°N latitude, where a traditional rice - wheat cropping system prevails. Its

better performance results from the unique combination of traits inherited from both parents (see table).

It is acceptable to farmers in Henan, Anhui, Jiangsu, Jiangxi, and Guizhao Provinces, with more than 50,000 ha planted.

Performance of some promising rice cultivars for tidal marshy swamps of Andamans

A. B. Mandal, N. D. Majumder, and A. K. Bandyopadhyay, Central Agricultural Research Institute, Port Blair, Andamans 744101, India

Agronomic traits related to tolerance for salinity of some promising rice cultures in the marshy swamps of Andamans. a

Panicle- Panicle Phenotypic Days to Plant height bearing length Seed yield/

Designation Source index 50% (cm) tillers (no.) (cm) plant (g)

(a) (r) (a) (r) (a) (r) (a) ( r ) (0-9) flowering b

88-027 IRRI 6 155 88-048 IRRI 9 na 88-092 IRRI 5 153 88-127 IRRI 3 153 88-091 IRRI 4 130 88-121 IRRI 4 148 88-106 IRRI 4 150 88-104 IRRI 7 135 88-097 IRRI 7 88-088 IRRI 7 160 88-038 IRRI 5 140 88-063 IRRI 4 155 88-006 IRRI 5 121 88-126 IRRI 5 145 88-012 IRRI 6 na 88-080 IRRI 6 88-032 IRRI 3

na

na 147

88-071 IRRI 9 120 SR26-B India 3 129 CO 43 India 5 137 CST100-1 India 5 140 CSR3 India 5 153 316 India 5 138 F35 India 5 129 C-14-8 India 5 155

a (a) = actual value under saline condition.

51.0 47.4 6.0 83.3 12.6 54.3 6.0 27.8 55.5 58.2 3.4 68.0 16.5 68.5 6.8 52.3 41.8 45.5 7.0 74.5 18.3 72.7 7.0 23.3 49.0 54.8 6.0 76.9 17.4 83.3 8.4 44.9 51.6 57.2 4.3 69.4 18.6 78.8 11.2 82.4 58.8 64.1 5.0 62.5 19.5 95.6 14.0 35.0 61.4 67.3 3.4 77.3 19.6 86.7 3.4 38.6 62.2 70.7 3.4 77.3 21.3 99.1 7.5 56.8 51.4 60.7 3.8 76.0 12.6 64.3 7.6 25.3 48.0 51.7 3.3 37.5 14.3 74.5 6.9 19.6 59.5 73.5 5.0 89.3 15.1 83.9 15.0 53.6 42.3 54.4 4.5 88.9 18.3 80.3 4.0 49.4 44.7 62.1 3.0 50.0 9.9 57.6 3.0 25.0 72.0 81.6 4.0 64.5 16.2 70.7 4.4 29.5 48.9 53.6 4.5 62.5 17.5 81.4 9.0 57.0 46.3 52.4 4.0 71.4 13.7 59.6 4.0 39.6 79.0 74.8 6.0 51.7 18.8 88.3 8.4 18.1 52.5 56.0 3.2 84.2 16.2 69.2 3.2 28.1 95.6 93.3 3.0 83.3 11.6 56.9 3.0 38.0 55.8 66.1 4.0 76.9 14.8 67.9 4.0 29.6 52.6 87.1 3.8 95.0 15.4 92.2 5.7 47.5 51.8 68.6 2.2 47.8 15.3 86.0 4.0 43.5 59.8 68.7 3.5 83.3 14.3 69.8 2.7 29.3 58.5 68.3 5.0 84.0 12.6 68.9 4.2 84.0

142.4 87.4 5.4 58.6 20.6 86.9 11.6 50.4

performance under saline condition × l00 performance under normal condition

(r) = relative value =

b na = not available.

26 IRRN 14:4 (August 1989)

Zhongyu 87-1, promising line developed through shuttle breeding

Min Shao Kai and Lu Ze Tung, China National Rice Research Institute (CNRRI), Hangzhou, Zhejiang; G. S. Khush and A. Evangelista, IRRI; and Tang Shaoqing, CNRRI, Hangzhou, Zhejiang, China

Zhongyu 87-1—a high-yielding, medium-duration, multiple-resistance, and wide-adaptability variety developed from the cross Kwangluai 4/IR64 through the IRRI-CNRRI Shuttle Breeding project—can be grown in middle season or late season. It is resistant to blast and whitebacked planthopper and moderately resistant to bacterial blight and brown planthopper.

demonstration test in Zhejiang Province, it yielded higher than Shanyou 6 (hybrid check) in five of six sites (Table 1). In farmers' fields in Zhejiang, it averaged 7.5 t/ha, 7.26% higher than Shanyou 6. In preliminary regional adaptability tests in Hubei Province in middle season 1988, its yield was significantly higher than that of check variety Quichao 2 in three locations (Table 2).

100 cm), compact plant type, and

In a late season 1988 hybrid rice

Zhongyu 87-1 has medium height (90-

Table 1. Performance of Zhongyu 87-1 in late season hybrid rice demonstration test. a Zhejiang, Table 2. Yield of Zhongyu 87-1 in midseason China, 1988. rice preliminary regional adaptability tests.

Hubei, China, 1988. Height Panicles Grains/ Sterility 1000- Yield Increase over

Location /hill panicle grain wt (t/ha) Shanyou Yield a Increase over Rank

Quxian 78.7 9.7 99.3 10.6 29.4 7.1 14.8 Huangyan 81.0 10.3 105.7 13.6 30.8 7.5 5.0 Wuhan 7.1** 16.5 1 Fuying 83.8 10.4 112.6 12.0 27.8 8.8 42.0 Dongxihu 9.6** 11.6 2 Shuichang 75.1 10.9 91.9 23.1 26.9 5.1 -3.5 Jinzhou 8.5** 17.3 1 Wenlin – 11.3 116.1 9.7 26.1 8.3 14.3

(m) (no.) (%) (no.) (g) 6 (%) Location (t/ha) Quichao 2 (%)

test b

Lequing – 12.0 111.6 15.4 27.5 7.4 2.2 a Of 11 varieties. ** = significant at P = 0.01.

a Plot size = 133 m 2 .

lodging resistance. Panicles are large (106-110 grains/panicle) and grain-filling rate high (85%), with 27-29 g/1,000 grains and 22-23% amylose content. In 1989, Zhongyu 87-1 was promoted to regional adaptability tests in Hubei and

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Zhejiang.

Data management and computer modeling

Simulation of yield potential The program took into account dry matter accumulation, physiological characteristics, and weather prevailing

in rice cultivars

R. Sadasivam, S. Mohandass, and A. Arjunan, Crop Physiology Department, Tamil Nadu Agricultural University (TNAU), Coimbatore; and S. Palanisamy and N. Raju, Tamil Nadu Rice Research Institute, Aduthurai, Tamil Nadu, India

We raised six lowland rice cultivars available from the gene bank of the Paddy Breeding Station, TNAU, Coimbatore, during 1988 wet season and conducted productivity studies. Yield potentials were computer simulated using the MACROS. L1D simulation model developed by IRRI.

during the growth period.

are presented in the table. Measured grain yields within 10% ±100% of calculated grain yield are presented in the figure.

yield agree satisfactorily in ADT36, ADT37, CO 37, and ASD16.

This shows that yield potential and production can be reasonably estimated on the basis of cultivar physiological characteristics and growing area weather Calculated and measured grain yield for rice conditions. cultivars. Coimbatore, India.

Observed and calculated grain yield

Calculated grain yield and measured

Calculated and measured main yield of rice cultivars at Coimbatore, Tamil Nadu, India.

Calculated Measured Cultivar grain yield grain yield Simulation Kuttanad usually coincides with the

percentage rainy season. Popular high-yielding

Seed technology Harvest of the second (Feb-Jun) crop at

(t/ha) (t/ha)

Screening rice varieties for ADT36 6.8 6.2 varieties grown during the second season

91.2 ADT37 5.1 4.8 94.1 grain dormancy lack seed dormancy and considerable CO 37 7.2 7.0 97.2 loss occurs due to grain sprouting in the ASD16 5.2 TKM6

5.1 2.3 3.1

98.1 S. L. Kumary, S. K. Ommen, and C. A. field. IR66 4.1 5.6 136.6 Joseph, Kerala Agricultural University, Rice We screened germplasm at RRS

Research Station (RRS), Moncompu, India Moncompu for grain dormancy to

IRRN 14:4 (August 1989) 27

in

134.8

Grain dormancy a of rice varieties and cultures in Kuttanad, India.

Strong dormancy

Chennellu, Karivennel, Kuruka, Pokkali 372, Chettiviruppu, RP 106, MO 1, MO 4, Cul. 12814, 31-2-1, 126, 168, 83-1-1, 65-2-3-1, 23-7-1-1, 14-14-2-3, 305-2, 106-1-1

Moderate dormancy

Vykatharyan, Nan- diarvattom, Sulekha, Cul. 93, 170, 1459-2, 214-1, 166-1-2, OS4, 1539-2

a Strong = 5-25% dormancy, moderate = 25-50% dormancy.

identify donor parents for developing appropriate varieties.

varieties, high-yielding varieties, and prerelease japonica/ indica cultures. Panicles were collected 1 wk before maturity, at maturity, and 1 wk after maturity and sun-dried to 13-14% moisture. The dried panicles were soaked 12 h in water, drained, and kept at room temperature 36 h to measure germination.

Test cultivars included local tall indica

Of the 85 entries screened, 28 possessed moderate to strong dormancy (see table).

For instructions on preparation of brief reports of rice research to submit for publication in IRRN, see the inside front cover of this issue.

CROP AND RESOURCE MANAGEMENT Crop management

Yields of broadcast and transplanted Oryza glaberrima floating rice

W. Schreurs, UNDP/UNCDF, Mali, West Africa

Despite the generally assumed superiority of O. sativa, many farmers in West Africa still prefer O. glaberrima. In field observations in Tombouctou, Mali, O. glaberrima was more drought tolerant and had greater vegetative vigor than O. sativa varieties grown in Mali.

Yields of O. glaberrima in farmers’ fields averaged 2.5 t/ha (highest yield

Table 1. O. glaberrima floating rice yields in farmers’ fields. Tombouctou, Mali, 1987.

Village Variety Establishment Yield a

(t/ha)

Tourchauane Tourchauane Tourchauane Gourzouguay Gourzouguay Gourzouguay Banikane Banikane Hondou bomo koyna Hondou bomo koyna Hondou bomo koyna Hondou bomo koyna Bozo Bozo Chembu Chembu Chembu Chembu Chembu Sanfatou Bougouni

Bori Bori Hondou bomo koyna Hondou bomo koyna

Average yield

Average yield

Dembu Dembu Dembu Dembu Dembu Dembu Dembu Dembu Jinga Jinga Jinga Dembu Dembu Dembu Dembu Dembu Dembu Dembu Dembu Dembu Dembu

Jinga Jinga Kossa Dembu

Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast Broadcast b

Broadcast b

Broadcast b

Broadcast b

Broadcast b

Broadcast b

Broadcast b

Broadcast b

Broadcast b

Transplanted Transplanted Transplanted Transplanted

3.7 3.4 4.4 0.7 2.3 1.4 1.4 1.4 2.6 2.5 2.3 3.2 3.4 3.1 3.1 2.0 3.6 3.0 1.6 1.4 1.5 2.5 2.4 2.3 1.2 1.2 1.8

a Sample plot size was 25 m 2 , 10% was deducted from sample dry weight to account for sampling errors. b Received some additional irrigation (by motor pump) during establishment.

was 4.4 t/ha) (Table 1). One reason for the relatively high yield may be that the crop is harvested at maximum water levels (from canoes), when culms are standing upright in the water. Crop disturbance and subsequent grain shattering (the primary cause of low O. glaberrima yields) are kept to a minimum.

Because of frequent crop failure due to lack of rain, farmers recently have begun to try transplanting floating rice in floodwater. The data seem to indicate that yields of transplanted floating rice are lower than those of broadcast rice. However, only four fields of transplanted rice were surveyed. We studied transplanting in a single- replication trial (plot size 13 m 2 ) using both O. sativa and O. glaberrima varieties (Table 2). Four-wk-old

Table 2. Grain yield and growth duration of transplanted floating rice. Tombouctou, Mali, 1987.

Yield Growth

(t/ha) duration (d)

Oryza glaberrima Dembu cirai Dembu banekanna Kossa bibi Jinga Oryza sativa

DM16 Nang Kieuw Khao Gaew

FFRS43-3

3.9 2.9 2.2 1.4

3.7 3.5 2.3 0.8

112 112 103 90

120 117 125 130

28 IRRN 14:4 (August 1989)

seedlings were transplanted at 15-cm spacing. Water rose at 2-3 cm/d to a maximum water depth of 112 cm. Neither species had superior yield, but O. glaberrima showed more vigorous vegetative growth.

Varietal differences in milled quality of rice harvested at different maturities

A. C. Roy and J. B. Fokou, IRA-Dschang, P.O. Box 44, Dschang; and S. B. C. Wanki, Upper Nun Valley Development Authority (UNVDA), P.O. Box 25, Ndop Plain, Cameroon

Rice varieties differ in grain form, milling outturn, and market price. Harvesting at different stages of maturity also affects head rice outturn and grain breakage.

Preliminary farm surveys during the 1986 crop season showed that most farmers in the Upper Nun Valley do not follow recommended practices for time of harvest. Many leave their crops in the field after maturity, harvesting when they have time. Rice harvested at different maturity stages mills out with high percentage brokens and very low percentage head rice.

We grew four promising varieties and lines in nonreplicated large plots (500 m2) at Bamunka Rice Research Station, Ndop Plain, and harvested 100 m2

subplots at intervals of 5 d, from 35 d after heading (DH) to 60 DH. The yields (20-40 kg rough rice/sample) were sun-dried to about 12-14% moisture, hulled, and polished using a Satake rubber roll rice mill (model SB 100). Percentages brown rice, head rice, broken rice, and marketable rice were taken for each sample. (Head rice is defined as whole milled rice, marketable rice as grains 50-100% as long as whole milled rice.) Estimated 1,000-grain weights of rough rice and brown rice also were noted for each harvest date.

Total brown and clean milled rice varied with varieties, from 73.8 to 81.7% brown rice and 63.5 to 71.3% clean milled rice, but were not markedly affected by harvest date (see table).

Effect of harvesting rice at different stages of maturity on milling outturns. Ndop Plain, Cameroon, 1987 wet season.

Harvest Rough rice

(DH) a at harvest (%) Brown Clean Head b Marketable

Percent of rough rice

Variety or line date moisture

rice rice rice c

RNR29692 35 40 45 50 55

IR7167-33-2-3 40 45 50 55 60

B29838-SR-51-2-1 40 45 50 55 60

B2161-C-MR-57-1-3-1 35 40 45 50 55 60

27.6 27.1 22.0 20.0 18.0

30.4 26.5 24.5 22.5 12.8 29.4 26.5 24.4 22.5 14.1 30.9 29.4 26.5 24.5 18.7 11.5

73.8 66.4 58.7 75.5 69.5 58.3 79.3 68.5 57.5 79.0 65.8 35.6 81.0 69.1 46.9

81.3 71.1 42.1 77.7 71.3 30.0 77.1 67.5 19.9 79.5 66.2 8.7 80.1 71.2 10.0

80.5 63.5 23.2 79.2 68.9 33.5 75.7 64.9 13.8 78.6 67.8 14.5 77.7 65.5 5.1 75.7 62.7 16.5 74.0 66.2 13.1 77.4 67.0 19.2 81.2 63.2 14.3 77.1 68.7 7.1 81.7 67.3 3.7

64.1 67.6 65.6 60.4 65.8

68.5 66.7 61.6 55.9 63.0 53.2 59.0 50.3 52.3 45.0 40.2 51.0 56.8 46.5 55.2 44.9

a DH = days after heading. b Head rice = % whole milled rice. c marketable rice = 50% or more than the length of whole milled rice.

RNR29692 had the highest (51.4%) and B2161-C-MR-57-1-3-1 the lowest (12.3%) head rice.

Grain maturity stage profoundly affected percentage brokens. Harvest more than 45 DH resulted in very high percentage brokens.

Extremely high, percentage brokens in all varieties (except RNR29692) harvested 40 DH and later tend to limit their adaptability as commercial varieties.

RNR29692 yielded higher than IR7167-33-2-3 at Ndop Plain. Both lines have medium-long grain with high amylose content (28,3%); B2161-C-MR- 57-1-3-1 and B29838-SR-51-2-1 have medium-long grain with intermediate amylose content (23.7%). Because of its high head rice percentage, RNR29692 is under consideration for release as a commercial variety, subject to local consumer acceptance and other qualities.

Effect on yield of cutting deepwater rice for herbage

S. K. Bardhan Roy, B. Banerji, C. Kundu, and B. K. Mandal, Rice Research Station, Chinsurah, West Bengal, India

During the 1988 wet season, we cut leaves of variety CN705-18 (CN645/ Mahsuri) at different growth stages. The first cutting of the 10 May direct seeded crop was done 110 d after seeding in two plots. A second cutting was done 130 d after seeding

(immediately before panicle initiation) in only one plot. Water level at cutting was 50-60 cm (maximum water level 90 cm was in late June). Only leaves above the water were cut, leaving 5 cm of leaves intact.

Foliage yield, grain yield, and yield components were measured. The first cut in plot A produced 3.8 t green leaves/ha and in plot B, 3.6 t green leaves/ ha. The second cut in plot B only 20 d after the first cut produced 3.4 t green leaves/ ha (Table 1). Grain yields in single cut and uncut crops were

IRRN 14:4 (August 1989) 29

rice

Preliminary results show that a hand- held chlorophyll meter comes closer

than any other technique as a simple, quick, and accurate method for predicting the need to topdress N in semidwarf rice. A relationship between the chlorophyll content of the newest expanded leaf and the need for N fertilizer has been developed in 2 yr of experiments in research plots at Beaumont and in 1 yr at Bay City and Eagle Lake, Texas (see table).

We tested semidwarf Lemont variety

F. T. Turner and M. F. Jund, Texas A&M Agriculture Research and Extension Center, Route 7 Box 999, Beaumont, Texas 77713, USA

Using a chlorophyll meter to predict need for topdressed nitrogen

Table 1. Foliage and grain yield from CN705- 18. Chinsurah, India, 1988.

Parameter (no cut) Control 1 cut 2 cuts

Foliage yield (t/ha)

1st cut – 3.8 3.6 2d cut – – 3.4 At harvest 2.1 1.9 2.0

Total 2.1 5.7 9.0 Grain yield (t/ha) 1.0 1.1 1.4 Days to 50% 171 175 167

flowering

similar. Yields in the double cut crop were higher. Flowering was early in the double cut crop, followed by the normal crop and by the single cut crop.

Number of effective tillers at harvest was significantly higher in the double cut crop and 1,000-grain weight

Improving rice yield using hydrocortisone spray

K. Manian, R. Govindarasu, P. Sivasubramanian, and N. Natarajaratnam, Pandit Jawaharlal Nehru College of Agriculture, Karaikal 609605, Union Territory of Pondicherry, India

The effect of hydrocortisone, a glucocorticoid hormone of higher animals, has been found to be beneficial for germination of rice. We assessed the effect of hydrocortisone on dry matter production, grain yield, and harvest index.

at different growth stages—active tillering phase (50 d after sowing [DAS]), flowering (75 DAS), and grain filling (100 DAS)—of a standing crop of IR20 at Karaikal. Spraying at flowering significantly improved grain yield and increased dry matter production (see table). Dry matter production increased most with spray at active tillering phase, but yield increased only 12%.

This trend suggests that dry matter production is stimulated by hydrocortisone spray during tillering phase, but its use for increasing grain productivity is limited. Similarly, spraying at grain filling phase did not

Hydrocortisone (50 ppm) was sprayed

30 IRRN 14:4 (August 1989)

Table 2. Effect of leaf cutting on yield components. Chinsurah, India.

Character Treatment Percent increase or

decrease over control No cut 1 cut 2 cuts

Plant ht (cm) Effective tillers at harvest (no.) Panicle length (cm) Total grains per panicle 1000-grain wt Percent of sterile grains/panicle Yield per plant (gm) Grain-to-straw ratio

205.0 6.0

23.4 202.0

24.1 1.9

28.0 0.5

200.0 10.0 22.0

185.0 24.3

3.6 41.0

0.5

182.0 12.0 22.5

156.0 25.4

4.2 45.0

0.7

– 11 + 100 – 4 – 23 + 5

+ 61 –

–

increased slightly. Grain yield/ plant and contributed to better grain filling. grain-to-straw ratio also increased. Plant This preliminary study shows that height, total grains/panicle, and length herbage production is possible with of panicle were reduced (Table 2). photoperiod-sensitive deepwater rice,

The increased number of effective without sacrificing grain yield. tillers contributed 61% of the yield increase. The shorter plant height

Effect of spraying hydrocortisone at different growth stages on yield, dry matter production, and harvest index per plot basis (16 m 2 ). a Pondicherry, India.

Control Active Flowering Grain filling LSD

(50 DAS) tillering (75 DAS) (100 DAS) (5%)

Yield (g) 9.10 10.21 11.00 10.30 (12) (21) (13)

1.16

Dry matter production (g) 21.81 26.38 25.58 (21) (17)

24.70 (13)

4.04

Harvest index 0.41 0.39 0.43 0.41 ns (-6) (4) (-2)

a Figures in parentheses indicate percentage increase over control.

improve grain yield or dry matter simultaneously, a spray or production. To improve dry matter hydrocortisone of 50 ppm at flowering production and grain yield stage is optimum.

Soil fertility and fertilizer management

Relationship between leaf chlorophyll content and rice yield. Beaumont, Texas.

Chlorophyll yield

(t/ha)

20 1.4 93 30 0.7 37 35 0.4 17 40 0.1 (–3 )

Expected Expected net

increase topdressing N ($) reading return to

Economy in combining fertilizer N with green manure in lowland rice

G. Shukla, P. C. Pandey, P. S. Bisht, and P. Lal, Agronomy Department, G.B. Pant University of Agriculture and Technology, Pantnagar, Nainital 263145, Uttar Pradesh, India

We studied the integrated effect of organic + inorganic N on rice yield and N use efficiency and recovery during wet season 1988. The experiment was laid out in a randomized block design with four replications. The soil is silt loam classed as Aquic Hapludoll, with pH 7.9, 1.1% organic C, CEC 20 meq/100 g, and 0.1% total N.

For green manure, 50-d-old crops of Sesbania rostrata and S. aculeata were chopped and incorporated into the top 15 cm soil at 10 and 20 t/ha, respectively, 1 wk before transplanting. Farmyard manure (FYM), 20 t/ha fresh weight basis, was incorporated 1 mo before transplanting. Pant Dhan 4 was sown 1 Jun and transplanted 11 Jul. All plots received 17.6 kg P, 24.2 kg K, 10 kg Zn/ha before transplanting. N was applied per treatment (see table).

Yield with Sesbania alone equaled yield with 90 kg N as prilled urea (PU). Sesbania with 30 kg N as PU increased the grain yield 9%, which was significantly higher than that with 90 kg N as PU alone and equaled yield with 120 kg N as PU or USG.

Highest N use efficiency and apparent N recovery was with Sesbania alone.

S. rostrata proved no better than S. aculeata, probably because it had only half the biomass.

topdressed with 45 kg/ha 2 wk before and at panicle differentiation. Net income due to topdressing decreased as leaf chlorophyll increased.

When chlorophyll readings were near 39 and higher, there was no economic advantage to topdressing N (assuming urea = $165/t, application cost = $8.64/ha, and rice value = $8/cwt).

The chlorophyll meter (model SPAD- 501 developed by Minolta) does have limitations: initial cost = $1400. But fertilizing a 40-ha field with 45 kg N/ha also = approximately $1400. Another limiting factor is that leaf chlorophyll can be influenced by P, Zn, and Fe deficiencies; low temperature; rice variety; growth stage; and herbicides.

Effect of organic and inorganic N source on yield, N uptake, N use efficiency, and apparent N reco- very in rice. a Pantnagar, India, 1988.

Treatment

Time and rate of N Grain N uptake (kg/ha) N use efficiency Apparent N

Basal PU Total N yield (kg grain/ through 6-7 DBPI (kg/ha) (t/ha) Grain Straw Total kg N applied)

recovery (%)

GM PU

Control 0 0 0 0 3.8 54 24 78 USG 0 80 40 120 5.8 95 61 156 PU 0 80 40 120 5.7 93 46 139 PU 0 50 40 90 5.4 82 51 133 SA b + PU 60 20 40 120 6.1 101 55 155 SR b + PU 40 40 40 120 6.1 100 55 155 FYM b + PU 50 30 40 120 6.1 100 45 145 SA + PU 60 30 0 90 6.0 100 44 144 SR + PU 40 30 0 70 5.8 96 42 138 FYM + PU 50 30 30 110 5.0 77 38 118 SA 60 0 0 SR

60 5.3 87 46 113 40 0 0 40 5.2 75 33 108

LSD (0.05) 0.4 6 7 11

17 16 18 19 19 19 24 29 11 25 38

–

–

65 51 61 64 64 56 73 86 36 92 75

–

–

a GM = green manure, USG = urea supergranule (46% N), PU = prilled urea (46% N), SA = Sesbania aculeata (2% N, 80% moisture), SR = Sesbania rostrata (1.75% N, 83% moisture), FYM = farmyard manure (0.5% N, 50% moisture). b N content in sesbania and FYM was analyzed, The remaining N was applied through PU to meet the basal requirement of 80 kg N/ha. The rest or 1/3 of 120 kg N was applied at 6-7 d before panicle initiation (DBPI).

Effect of deep-placed urea urea (PU) alone and in combination

supergranules (USG) with with limited amounts of Gliricidia

limited green manure on transplanted rice yield

sepium leaves on rainfed transplanted rice.

The 11 treatments were laid out in 15-

S. S. Dhane, R. R. Khadse, and V. H. Patil, Regional Agricultural Research Station (RARS), Konkan Krishi Vidyapeeth (KKV), Karjat, Maharashtra State 410201, India; and N. K. Savant, International Fertilizer Development Center (IFDC), P. O. Box 2040, Muscle Shoals, Alabama 35662, USA

The amount of green manure available in small rainfed rice farmers’ fields is likely to be very limited. In 1988 wet season, we compared the effect of deep- placed USG and split-applied prilled

m 2 plots on the RARS farm, Karjat, in a randomized block design with three replications. Soil was clay loam with pH (1:2.5 soi1:water) 7.0 and cation exchange capacity 30 meq/100 g. All plots received 17 kg P/ha as single superphosphate and 33 kg K/ha as potassium chloride.

PU (38 kg N/ha) was applied 50% broadcast and incorporated before transplanting and 50% topdressed before panicle initiation. USG (1-g pellets) was hand placed about 10 cm deep during

IRRN 14:4 (August 1989) 31

line transplanting, one pellet every four hills (15 × 20 cm). Quantities of gliricidia green leaves (containing 2.7% N ovendried basis) to supply 0, 1, 1.5, 2, and 2.5 t green manure/ ha were spread uniformly over freshly puddled soil before line transplanting. Karjat-184 was transplanted (3-wk-old seedlings) 7 Jul and harvested 12 Oct.

Deep-placed USG significantly increased grain and straw yields (see table). Deep-placed USG at 38 kg N/ha plus green manure increased grain yield more than split-applied PU.

Integrated nutrient management in irrigated rice M. R. Patel, N. P. Chauhan, S. A. Patel, and J. G. Patel, Gujarat Agricultural University, Main Rice Research Station, Nawagam, Gujarat, India

We studied the integrated effect of organic and inorganic sources of N on growth and grain yield of rice variety GR11 during 1987 wet season. Eight fertilizer combinations were tested (see table).

The test soil was sandy loam with a pH of 7.3, EC 3.5 dS/m, 0.065% total N, 68.5 kg available P/ha, and 332.8 kg available K/ ha.

P and K were applied basally; N as ammonium sulfate was applied in four equal splits; basal and at tillering, panicle initiation, and dough stage.

Effect of USG and PU with limited gliricidia green manure on rainfed transplanted rice yield. a Maha- rashtra, India, 1988 wet season.

Treatment

Urea N (kg/ha)

Green manure Yield (t/ha) Tillers/hill

t/ha kg N/ha Grain Straw

0 0 0 2.8 c 3.1 d 38 (PU) 0

7.9 e 0

38 (PU) 1 3.0 c 3.2 d 9.7 de

6.3 2.9 c 3.4 d 38 (PU)

12.5 abc

38 (PU) 1.5 9.5 2.9 c 3.2 d 2 12.6

10.3 cde 3.2 bc 3.8 cd

38 (PU) 11.1 bcd

38 (USG) 2.5 15.8 3.5 b 4.5 bc 0 0 3.8 ab 4.7 bc

11.9 bcd

38 (USG) 1 13.0 ab

6.3 3.9 a 38 (USG) 1.5

5.1 ab 9.5

13.5 ab

38 (USG) 2 4.0 a 5.7 a 12.5 abc

12.6 38 (USG)

4.2 a 5.5 ab 2.5

14.6 a 15.8 3.9 a 5.2 ab 15.1 a

a In a column, means followed by the same letter are not significantly different at the 5% level by Duncan’s Multiple Range Test.

(no.)

Azolla was inoculated at 1 t/ha 10 d Effect on rice yield of N after transplanting (DT). Because of an applied during reproductive erratic rainy season, water was not impounded and azolla grew very poorly.

phase The azolla mat was incorporated 30 DT.

Sesbania aculeata was incorporated 1 d before transplanting.

Before incorporation azolla had 2.8% N, 0.48% P, and 3.2% K; S. aculeata had 2.5% N, 0.64% P, and 1.0% K.

Delayed planting due to failure of the monsoon and use of brackish irrigation water from a bore well decreased yields.

Grain yield with S. aculeata + 40-20- 20 kg NPK/ ha and S. aculeata + 0-20- 20 kg NPK/ ha were significantly higher than all other treatments except 80-40- 40 kg NPK/ ha alone and S. aculeata + azolla + 0-20-20 kg NPK/ ha.

Effect of organic and inorganic sources of N on yield and panicles/m 2 . Nawagam, India.

Treatment Grain yield Panicles/m 2 Biomass (t/ha)

(t/ha) (no.) incorporated

Control 0.8 0-8.8-16.6 kg NPK/ha 0.8 40-8.8-16.6 kg NPK/ha 2.0 Azolla + 0-8.8-16.6 kg NPK/ha 1.0 Azolla + 40-8.8-16.6 kg NPK/ha 1.9 Sesbania aculeata + 0-8.8-16.6 kg 3.3

Sesbania aculeata + 40-8.8-16.6 kg 3.7

Sesbania aculeata + azolla + 0-8.8-16.6 2.8

80-17.6-33.2 kg NPK/ha 3.1 LSD (0.05) 1.1

NPK/ha

NPK/ha

kg NPK/ha

108 128 196 119 171 307

300

240

25 8 75

– – –

3.2 1.8

26.4

22.7

24.9 +1.5 –

P. C. Pandey, P. S. Bisht, and P. Lal, Agronomy Department, G.B. Pant University of Agriculture and Technology, Pantnagar, Nainital 263145, Uttar Pradesh, India

In the subtropical climate of north India, rice grown with recommended best N split (1/2 basal, 1/4 at tillering, 1/4 1 wk before panicle initiation) or standard split (2/3 basal, 1/ 3 1 wk before panicle initiation) has luxuriant vegetative growth but the canopy turns light green during ripening. We tested supplying a larger proportion of N during reproductive stages (1 wk before panicle initiation, at booting, and at heading), at 120 and 180 kg N/ha. The field experiment was laid out in a split- plot design with four replications in wet season 1988 at Pantnagar (29° N, 79° 29' E, 244 m).

Soil was silt loam with pH 7.9, 1.1% organic C, CEC 20 meq/ 100 g soil, 0.1% total N, 13.9 kg available P/ ha (Olsen), and 202 kg available K/ ha (NH 4 OAc extraction).

Pant Dhan 4 (134 d duration) was sown 1 Jun and transplanted 5 Jul with basal application of 17.6 kg P, 24.2 kg K, 10 kg Zn/ha.

32 IRRN 14:4 (August 1989)

Effect of single superphosphate and granular superphosphate fertilizer on rice yield

M. L. Adil, J. R. Patel, and S. C. Mukharjee, Indira Gandhi Krishi Vishwa Vidyalaya, Raipur 492012, Madhya Pradesh,

India

We compared response of rice to single superphosphate (SSP) (16% water soluble and 2% citric soluble P 2 O 5 ) and granular superphosphate (GSP) (14.8% water soluble and 3.6% citric soluble P 2 O 5 ) during 1987 wet season.

Medium-duration cultivar Kranti was transplanted 20 Jul 1987 and harvested 4 Nov 1987. Soil was medium heavy (sandy loam) with pH 6.7, 0.42% organic C, CEC 32.6 mg/100 g, and 210 kg available N, 10.5 kg available P, and 325 kg available K/ha. All treatments received 60-40-20 kg NPK/ha except that the control plot received no P. N was applied in three splits: 50% basal, 25% topdressed at tillering, and 25% at panicle initiation.

For both SSP and GSP, treatments were all P as basal, all P at tillering, and

split P, 50% at transplanting and 50% at tillering.

The experiment was laid out in a randomized block design with three replications. Plot size was 144 m 2 ; plant spacing was 20 × 20 cm.

Reduction of rice yield without any P fertilization was significant (see table). Applied as basal, SSP was much superior to GSP. Yield was significantly higher with SSP split application.

The relatively higher availability of P in water-soluble SSP might have made the difference under wetland conditions.

Performance of Sesbania rostrata in acid soils

M. A. Salam, S. M. S. Hameed, P. Sivaprasad, E. Tajuddin, and Y. Thomas, Cropping Systems Research Center (CSRC), Karamana, Trivandrum 695002, India

We compared S. rostrata, a newly introduced green manure crop, with S. aculeata and Crotalaria juncea, green manure crops commonly grown in Kerala.

Effect of split N application on grain yield, panicle numbers, and filled grains and unfilled grains of rice. a Pantnagar, India, 1988.

N application Grain yield (t/ha) Panicles/m 2 (no.) Filled grains/panicie (no.) Unfilled grains (%)

Basal Tillering 6-7 Boot Heading N 120 N 180 Mean N 120 N 180 Mean N 120 N 180 Mean N 120 N 180 Mean DBPI b

1/2 1/4 1/4 –

1/5 1/5 1/5 1/5 1/5 1/4 1/4 1/6 1/6 1/6

2/3 – –

1/3 – –

Mean

Treatment

N rate Time of N application Interaction N rate at same or different time of application Time of N application within a N rate

CV (%) based on error b

6.2 6.8 6.5 184 183 184 136 6.5 6.8 6.7 182 193 188 126 6.9 7.9 7.4 183 197 190 147 6.9 7.4 7.2 191 188 190 141

6.6 7.2 185 190 138

LSD (0.05)

0.4 0.5

LSD (0.05)

ns ns

ns ns 7

ns ns 7

132 134 11 125 126 20 132 140 08 134 138 10

131 12

LSD (0.05)

ns ns

ns ns 7

17 14 19 20 12 10 10 10

15

LSD (0.05)

ns 4

ns

28 ns

a ns = nonsignificant. b Days before panicle initiation.

Response to N application time was topdressed 1 wk before panicle in yield was primarily due to more filled significant (see table). Applying N 1/5 initiation, booting, and heading grains per panicle. or 1/4 as basal and 1/5 or 1/6 N increased grain yield 10%. The increase

Effect of P source on rice yield and yield attributing characters. Raipur, India, 1988.

(t/ha) (t /ha) (no.) (cm)

Grain Straw Effective Panicle yield yield tillers length Treatment

Control (no P) GSP at transplanting SSP at transplanting GSP at tillering SSP at tillering GSP: 50% at transplanting,

SSP: 50% at transplanting, 50% at tillering

50% at tillering

LSD (0.05)

2.9 3.9 4.8 3.7 4.3 4.1

5.3

0.8

3.6 4.8 5.9 4.6 5.2 5.1

6.4

0.8

3.8 4.0 5.6 4.0 5 .0 5.0

5.8

ns

14.1 15.0 16.2 14.3 15.8 15.1

17.1

IRRN 14:4 (August 1989) 33

The field experiment was conducted during Jan-Mar 1988 (mean daylength 11 h 55 min) in acid soils (pH 5.0) of CSRC Karamana (11°N, 77°E and 30 m above mean sea level). The riverine alluvium, sandy clay loam soil contained 0.7% organic C and 100-7-10 ppm of available NPK with an EC of 0.3 dS/m.

The experiment was laid out in a randomized block design with eight

Disease management

Conidia release and dispersal pattern of Pyricularia oryzae under cloudy or rainy conditions

Chang Kyu Kim and Hong Sik Min. Plant Pathology Department, Agricultural Sciences Institute, Suweon 440-707, Korea; and R. Yoshino, Paddy Crop Disease Laboratory, National Agriculture Research Center, Tsukuba 305, Japan

We studied conidia release patterns from discrete blast lesions during 1988 rainy season in Korea, using a KY-type spore trap. On 13-14 Jul, it rained from 12 noon to 10 a.m. Conidia were released the entire time, with two distinct peaks between 1 and 7 a.m. (Fig. 1).

The first peak, 1-3 a.m., was due to the production of conidia from pre - existing conidiophores; the second peak, at 7 a.m., was due to conidia produced from conidiophores formed since 13 Jul evening. The peaks came by chance immediately after more than 16 mm rainfall/ h. More conidia were released from 7-d-old lesions.

We also observed conidia dispersal under rainy conditions 21-22 Jul, using a rotary spore trap (Fig. 2). Usually conidia dispersal during rainfall of more than 3.5 mm/ h is negligible, but in this experiment conidia dispersal was observed regardless of rainfall intensity. We believe that most of the conidia released and dispersed during rainy, cloudy conditions might be important as inoculum for blast epidemics.

34 IRRN 14:4 (August 1989)

replications. The crops were broadcast in Jan 1988 at 30 kg seed/ha. No fertilizers were applied. One irrigation was given at sowing for gemination.

Dry matter (DM) production and N yield were estimated using standard procedures at 50, 60, and 70 d after sowing (DAS).

Plant stands were uniform in all plots.

S. rostrata had the highest DMP and

1. P. oryzae conidia release pattern under rainy conditions in Suweon, Korea, 13-14 Jul 1988.

2. P. oryzae conidia and dispersal pattern in Suweon, Korea, 21-22 Jul 1988.

N yields at all three growth stages. At 50, 60, and 70 DAS, S. rostrata produced 5.0, 6.1, and 7.3 t DM, yielding 96, 145, and 153 kg N/ha, respectively. S. aculeata produced 4.7, 5.9, and 6.9 t DM, yielding 85, 131, and 140 kg N C. juncea produced 3.4, 5.3, and 6.3 t DM, yielding 68, 110, and 122 kg N/ha.

Yield loss due to rice blast (BI) disease at different crop stages

A. Surin, P. Arunyanart, R. Dhitikiattipong, W. Rodjanahusdin, K. Soontrajarn, S. Munkong, and S. Disthaporn, Rice Pathology Research Group, Plant Physiology and Microbiology Division, Bangkhen, Bangkok, Thailand

In 1984, leaf and panicle B1 caused by Pyricularia oryzae Cav. occurred extensively in Thailand. We conducted field experiments at Pathum Thani Rice Research Center during dry and wet seasons 1986 to determine rice yield loss to B1 at different crop stages.

Rice variety RD23 was direct sown in an 800-m 2 field and 513 sample units marked by binding units of approximately 10 tillers each with a string. Infected leaf area on each sample unit was estimated 45, 60, and 75 d after sowing (DAS).

All sample units were harvested and threshed separately and grain yield adjusted to 14% moisture content.

Data for each crop stage were grouped into classes of similar disease severity levels and average severity and average yield for each group calculated (Table 1). Average yield of group 1 was used to calculate yield loss of all other groups for a particular stage. Regression analysis was conducted on these new data sets.

2 show a high statistical precision. B1 All three, functions presented in Table

Table 1. Leaf Bl severity at different rice crop stages. Pathum Thani Rice Research Center, Thailand, 1986.

Disease severity (%)

Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Observation

Wet season 45 DAS 0-0.05 1 2 3 5-8 10 60 DAS 0-0.05 1 2 3 5 8-10 15-20 25-30 75 DAS 0-0.05 1 2-3 5 8-10 15 20 30

45 DAS 0-0.05 1 2 3 5-8 10 15 60 DAS 0-0.05 1 2 3 5-8 10 15 20-25 75 DAS 0-0.05 1 2 3 5-8 10 15 20-30

Dry season

Table 2. Relationship between leaf Bl severity and yield loss (y), derived from pooled data of two seasons. Pathum Thani Rice Research Center, Thailand, 1986.

Predictor variable a Regression function F b R 2

BLA 45 DAS y = 31.18 + 18.54* 1n (x) 121.2*** 0.92 BLA 60 DAS y = 9.38 + 2.99x 116.3*** 0.89 BLA 75 DAS y = 0.06 + 3.08x 355.1*** 0.96

a BLA 45 DAS = % leaf area infected at 45 days after sowing. b *** P < 0.001.

severity during the reproductive stage 1% infected leaf area corresponds to 3% (75 DAS) was most closely related to yield loss. yield loss. Based on the third function,

Estimating yield loss to rice blast (BI) disease

A. Surin, P. Arunyanart, R. Dhitikiattipong, W. Rodjmahusdin, and S. Disthaporn, Rice Pathology Research Group, Plant Pathology and Microbiology Division, Bangkhen, Bangkok, Thailand

Rice yield loss equivalents for leaf and neck Bl found in earlier experiments had to be derived from multiple regression functions, because of mixed infection by several diseases. We conducted a field experiment to study the effect on yield of Bl alone.

RD23 was direct sown 20 Aug 1986 at Pathum Thani Rice Research Center. A source of inoculum was provided near the experimental plot. Ten 0.5-m 2 plots were staked out in an area 800 m 2 . Incidence and seventy of rice Bl was observed two times, at maximum tillering (60 d after sowing [DAS]) and 1 wk before harvest. Data were collected on percentage leaf area infected, number of tillers, number of panicles, number of

Linear regression between leaf Bl percentage and percent yield loss at Pathum Thani Research Center, 1986 wet season.

panicles with neck Bl, filed grain weight, and empty grain weight.

Sample plots showed 0-70% infected leaf area. Neck Bl incidence was 11-35%. Leaf Bl severity was not correlated with neck Bl incidence ( r = 0.233 ns).

Yield of the plot free of leaf or neck B1 symptoms was used to calculate percentage yield loss in the other plots. Linear regression analysis resulted in a model to predict percentage yield loss from leaf Bl severity (see figure). The regression accounts for 78% of the variability in yield loss.

Reaction of four rice cultivars to grassy stunt virus (GSV) strain 2 under natural conditions

R. Devika, N. R. Bai, and C. A. Joseph, Rice Research Station, Kerala Agricultural University, Moncompu, India

During wet season 1988 (Jun-Jul to Oct- Nov), a severe outbreak of GSV in parts of Kuttanad, Kerala, caused severe damage to the rice crop. Serological tests at Directorate of Rice Research, Hyderabad, confirmed that the outbreak was caused by GSV strain 2. We evaluated MO 5, MO 6, KAU153-1, and KAU93 for resistance to this strain under three levels of fertilizer, in a split- plot design with three replications. Disease incidence was scored just before panicle initiation.

MO 5, MO 6, and KAU153-1 were moderately susceptible; KAU93 was susceptible (see table).

Resistance of rice varieties to GSV strain 2. Kerala, India, 1988 wet season.

GSV

(0-9) Cultivar Parentage damage

MO 5 IR11-1-66/Kochuvithu 5 MO 6 IR8/Karivennel 5

KAU93 Jaya/Ptb 33 7 KAU153-1 IR1561/Ptb 33 4

Control of blast (BI) in main field and nursery with some new fungicides

V. D. Naidu and G. V. Reddy, Andhra Pradesh Agricultural University, Agricultural Research Station, Nellore 524004, India

Bl causes considerable yield losses in Nellore District under favorable weather conditions from Oct to Feb. We tested seven EC/WP and four granular fungicides to control leaf and neck Bl in transplanted rice in wet seasons (Oct- Feb) 1985-86, using highly susceptible IR50.

Plots were laid out in a randomized block design with four replications.

IRRN 14:4 (August 1989) 35

^ ^ ^

^

Fertilizers, 180-60-30 kg NPK/ha, were applied, phosphorus and potash as basal and N in three splits: 1/3 basal, 1/3 at tillering, 1/3 at panicle initiation. Plant spacing was 15 × 15 cm.

EC/ WP fungicides were sprayed at tillering, panicle initiation, and flowering. Granular fungicides were applied 30 kg/ha when initial Bl symptoms appeared during tillering and 40 kg/ha during flowering. Leaf and neck Bl were measured 10 d after last application from five 1-m 2 random samples.

All the EC/WP fungicides but Natural Plant Product-1 effectively reduced leaf Bl (see table). Neck Bl was not reduced.

Granular fungicides chlobenthiazone 5 G and pyroquilon 5 G effectively controlled leaf Bl. Neck Bl incidence was not reflected in yield. Plots that showed

Influence of new EC/WP and granular fungicides on incidence of Bl and yield of IR50. Nellore, India. 1985-86.

Fungicide Concentration

EC/WP fungicides Carbendazim 50 WP 1 g/liter 2.2 24.3 Edifenphos 50 EC 1 ml/liter

1.6

Pyroquilon 50 WP 1.9 16.4

1 g/liter 2.2

Isoprothiolane 40 EC 1.7 26.3

1 ml/liter 1.9

IBP 48 EC 1.4 17.1

1 ml/liter 1.8

Natural Plant Product – 1 2.0 20.1

2.5 ml/liter 1.7

36.3 Thiophanate methyl 70 WP 1 g/liter

26.5 0.9 2.2

Untreated check 23.3

32.9 30.8 1.3 0.8

LSD (0.05) 18.6 ns 0.6 Granular fungicides Chlobenthiazone 6 G 70 kg/ha 2.0 32.2 Pyroquilon 5 G 70 kg/ha

2.4

IBP 17 G 70 kglha 0.7 20.4 3.0

39.4 Probenazole 8 G 70 kg/ha 21.6 0.9

17.2 46.7

1.5

Untreated check 81.5 10.3 0.5 LSD (0.05) 33.1 11.4 1.0

Leaf Bl Neck Bl Grain yield (%) (%)

(kg/plot)

more leaf Bl infection had few panicles on severely leaf Bl-affected plants only with neck Bl, perhaps because panicles partially emerged.

Insect management week. Three days on either side of a new moon was taken as a new moon week.

Effect of lunar phase on attraction of rice pests to black light trap

In-between periods formed the last and first quarter moon week. From total insect catches, ratios were obtained to compare full moon week catches with

D. Mohanraj, R. Janarthanan, and S. Suresh, Agricultural Entomology Moonlight had a significant effect on Department, Agricultural College and nocturnal activity of stem borer (SB), Research Institute, Tamil Nadu Agricultural leaffolder (LF), brown planthopper University, Madurai 625104, India (BPH), and green leafhopper (GLH).

We collected rice insect pests in a Krishi were l:l.l, 1:1.2, 1:2.2, and 1:2.3, Prakash Black Light Trap (KPBL-T) respectively (see table). This indicates during six lunar cycles. that nocturnal activity of SB and LF is

of a full moon was taken as a full moon that of BPH and GLH.

new moon week catches.

Full moon and new moon week ratios

Three days on either side of the date much less influenced by moonlight than

Effect of lunar cycle on the black light trap catches of some rice pests. Madurai, India.

Insects a (no.) Ratio of Insect full moon

Full moon Last quarter New moon First quarter week to new week week week week moon week

Yellow SB Scirpophaga 291.04 264.81 332.95 194.69 1:1.1

LF Cnaphalocrocis medinalis 169.73 176.88 202.25 63.76 1:1.2

BPH Nilaparvata lugens 159.80 157.14 376.11 128.45 1:2.4

GLH Nephotettix spp. 193.53 146.86 455.43 175.58 1:2.3

incertulas (1.94) (1.89) (2.30) (1.98)

(1.55) (1.90) (2.19) (1.50)

(2.00) (2.09) (2.47) (1.92)

(1.82) (2.10) (2.64) (2.09) a Mean of six lunar cycles. Figures in parentheses are transformed values.

Severe outbreak of rice gall midge (GM) in the savannah zone, Nigeria

M. N. Ukwungwu, Rice Research Program, National Cereals Research Institute, Badeggi, P. M. B. 8, Bida; and M. D. Winslow and V. T. John, Rice Research Program, International Institute of Tropical Agriculture, P.M.B. 5320, Oyo Road, Ibadan, Nigeria

The savannah zone of Nigeria, stretching latitudinally across the southern midsection, with its river floodplains and inland valley swamps, is an important rice-growing area. Production probably accounts for more than 70% of Nigeria’s total. Varieties grown include FARO 12 (Mas), FARO 13 (IR8), FARO 15, FARO 16, FARO 18 (Tjina or China), FARO 26 (TOs 78), FARO 29 (BG90-2), and IR5.

A severe outbreak of GM ( Orseolia oryzivora H & G.) damaged crops sown Jul-Aug 1988 (wet season). Earlier (Jun- Jul) crops had little damage.

The Abakaliki locality in Anambra State (8° 10' E, 6° 20' N) had the most severe damage. Incidence of silvershoots was high (45-80% of all tillers). Yields in

36 IRRN 14:4 (August 1989)

severely infested fields were essentially zero. The problem was serious throughout the rice bowl region, from the Benue River floodplain through Anambra, Cross River, and northern Imo State—an estimated 50,000 ha of rice.

Most farmers use varietal mixes, but no resistant or escape plants were seen in severely affected fields. Holdings in the area average about 0.5 ha; many farmers harvested no grain.

Although GM has been seen in the

Response of rice pests to mercury vapor light and black light traps

D. Mohanraj, R. Janarthanan, and S. Suresh, Agricultural Entomology Department, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai 625104, India

We compared the efficiency of two traps—a Modified Robinson Light Trap (MRL-T) with 80, 125, and 160 W mercury vapor lamps and a Krishi Prakash Black Light Trap (KPBL-T) with 40 W black light tube. The traps were located a minimum isolation distance of 100 m apart. Data were collected for 10 wk (19 Nov 1984-28 Jan 1985).

Sex and reproductive status of rice stem borers and leaffolders attracted to black light trap

D. Mohanraj, R. Janarthanan, and S. Suresh, Agricultural Entomology Department, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai 625104, India

We examined the sex ratio and reproductive status of rice yellow stem borer (YSB) Scirpophaga incertulas (Walk.) and rice leaffolder (LF) Cnaphalocrocis medinalis (Guenée) attracted to a 20 W black light trap. Insects were collected for 10 d the first 14 d of Nov 1984, when activity peaked. More YSB females than males were

West African savannah for many years, this is the most serious outbreak on record. Situations in 1988 that apparently favored the pest included unusually high rainfall early in the wet season (Jun-Aug); increased rice hectarage stimulated by price increases; small farmholdings with a wide range of planting dates that allowed continuous buildup of the pest population; and ample areas of grassy weeds surrounding the swamps that acted as alternate hosts.

Routine pesticide use is not appropriate for most farmers in this zone because of financial and logistical constraints, and health and environmental hazards. Intensification of breeding for varietal resistance is needed. We will test resistant germplasm from Asia at Abakaliki and Bida (also in the savannah zone) in the 1989 wet season to identify possible donors of resistance.

Catch of insects in different intensities of mercury and black light traps. a Madurai, India.

Insects collected (no.)

Total Stem borer Leaffolder Brown planthopper Green Trap

leafhopper

MRL-T 18,943.2 3,262.3 700.0 (125 W) (3.10) a (3.24) a

12,556.8 59,253.5 (2.53) b (3.26) a (3.45) a

(80 W) (3.11) a (3.21) a (2.45) b (3.27) a (3.51) a

(160 W) (2.92) b 327.5

(3.06) a 10,021.5 32,397.2

(2.11) b (3.13) a (3.41) a

(40 W) 2,287.0

(2.83) b (3.05) a (1.89) a (2.64) b (2.73) b

a Mean of 10 wk. Figures in parentheses are transformed values. In a column, figures followed by the same letter are not significantly different (P=0.05) by DMRT.

MRL-T 15,770.4 3,140.3 642.2 14,943.8 44,355.1

MRL-T 11,244.9 2,233.4

KPBL-T 1,373.6 1,063.5 839.5 1,304.3

MRL-T 125 W collected 40% and MRL-T 125 W; leaffolders to the MRL-T 80 W 33% of all insects KPBL-T. Brown planthoppers and collected (see table). green leafhoppers were more attracted

Stem borers were more attracted to to the MRL-T.

Reproductive status of SB and LF attracted to black light trap.

Days Total Male Female Gravid Spent Total Male Female Gravid Spent Stem borer Leaffolder

females females females females

1 118 10 108 55 93 74 2

53 323 156 167 174 18 156 92

3 195 12 183 105 64 334 143 191 118 73 78 328 164 164 96

4 258 14 244 140 104 232 104 128 68

5 306 16 290 160 130 328 135 193 120 78 50

6 197 9 188 126 73

62 224 98 126 7 98 4 94 63

86 40 31 158 84 74 44

8 340 6 334 186 148 214 115 99 30

9 188 12 176 113 58 41

63 69 34 35 10

23 360 15 345 200 145 112 55 57

12 35

Total a 2234 116 2118 1240 878 2322 1088 1234 751 483 22

(5.2) (94.8) (58.6) (41.6) (46.9) (53.1) (60.9) (39.1) a Values in parentheses are percentage of the total and of females, respectively.

attracted (see table); the male-to-female The ratio of male to female LF ratio was as high as 1:18. There were attracted was more or less equal. Of the more gravid females (58.6%) than spent total females, 61% were gravid and 39% ones (41.6%). spent.

IRRN 14:4 (August 1989) 37

Pentatomid bugs reduce rice grain quality in farmers’ fields in Orissa

S. P. Gupta, Central Plant Protection Station, Tulsipur, Cuttack 753008; A. Prakash, Entomology Division, Central Rice Research Institute, Cuttack 753006; A. Choudhury, Central Surveillance Station, Tulsipur, Cuttack 753008; J. Rao, Entomology Division, Central Rice Research Institute, Cuttack 753006; and A. Gupta, Zoology Department, College of Basic Science and Humanities, Orissa University of Agriculture and Technology, Bhubaneswar 751003, India

We surveyed farmers’ fields to study insects that reduce rice grain quality in Cuttack, Puri, and Balasore Districts, Orissa. In addition to rice stink bug Leptocorisa acuta (Thumb.), three new species of pentatomid bugs were found in both dry and wet seasons 1987-88. The bugs were identified as Eusarcoris ventralis Westw., Mendia histrio Fabr., and Nezara viridula Linn. (Pentatomidae : Heteroptera) at Zoological Survey of India, New Alipur, Calcutta.

Three villages were sampled per district. Bugs were collected from insecticide-free fields by net sweeping from five randomly selected 1-m 2 areas in each field. Five panicles also were collected randomly from each field; infested grains were counted to calculate grain damage (see table).

Insects were found during milky, soft dough, and hard dough stages in varieties Udaya, IR36, Ratna, MW10,

Grain damage in ricefields due to pentatomid bugs. Orissa, India, 1987-88.

Variety Grain damage a (%)

1987 1988

7.26 a 6.86 a dry season

Udaya dry season

MW10 8.12 a 10.24 b Ratna 13.23 b 14.75 c

1987 1988

3.97 a 2.89 a 2.34 a 5.54 b 3.97 a 8.06 b

wet season wet season Savitri Udaya IR36

years, numbers followed by the same letter do a Mean of 45 samples. Within columns and

not differ significantly.

38 IRRN 14:4 (August 1989)

and Savitri (CR1009). This was the first observation of E. ventralis, a stink bug, in India. Population densities in the dry season varied from 6.2 to 15.2 bugs (nymphs and adults)/m 2 in Udaya, MW10, and Ratna. In the wet season, populations varied from 1.73 to 8.54 bugs/m 2 in Udaya, IR36, and Savitri.

Green shield bug N. viridula also was found for the first time in India. Grains were infested during milky, soft dough, and hard dough stages. Population densities ranged from 5.5 to 9.6 bugs/ m 2

during the dry season and 1.2 - 4.3 bugs/m 2 during the wet season. This bug was not found in Savitri.

Weed management

Influence of herbicide carrier and application method on weed control

G. Srinivasan, G. K. Choudhury, and R. Jayakumar, Agronomy Department, Tamil Nadu Agricultural University, Coimbatore 641003, India

We studied the influence of various carriers on the performance of the herbicide mixture anilofos + 2,4-D ethyl ester (EE) (0.30 + 0.51 kg/ha) in the 1988 wet season. The experiment was laid out in a randomized complete block design with four replications. Applications were with a knapsack sprayer and 625 liters water/ha; sand- mix with 50 kg river-washed sand/ ha; prilled urea (PU) at 25 kg urea/ha; sprinkler bottle with herbicide volume made up to 2 liters/ ha; and hand weeding twice.

Herbicides were applied 6 d after transplanting (DT). Weed dry matter (DM) was measured 60 DT.

Weed flora included Echinochloa crus-galli, Cyperus difformis, Cyperus iria, Marsilea quadrifolia, Ammannia baccifera, and Eclipta rostrata.

Broadcast sand-mixed herbicide resulted in the least weed DM; PU as a herbicide carrier was equally effective (see table). (Using PU could reduce N

M. histrio, a shield bug, was found for the first time in Orissa. It sucks the sap during the milky stage and reduces grain weight. Population densities ranged from 7.5 to 17.1/m 2 in the dry season and 4.9 to 14.0 bugs/m 2 in the wet season.

the dry season. However, M. histrio predominated. Total grain damage ranged from 6.9 to 14.8% during the dry season and 2.3 to 8.1% during the wet season in different varieties. Grain damage differed significantly among varieties except in 1987 wet season.

Insect populations were higher during

Effect of herbicide carrier on weed dry matter production and rice grain yield. a Coimbatore, India.

Weed DM Grain Treatment b at 60 DT yield

(g/m 2 ) (t/ha)

Knapsack sprayer 9.5 b 5.4 a

Sand mix (50 kg 6.5 a 5.4 a

Prilled urea (25 kg/ha) 7.8 ab Sprinkler bottle 9.6 b

5.4 a 5.3 ab

Hand weeding twice 12.5 c 5.2 b

(625 liters water/ha)

sand/ha)

(20 and 40 DT) a In a column, means followed by the same letter are not significantly different at 5% level.

at 0.30 kg/ha and 2,4-D EE at 0.51 kg/ha. b The herbicide mixture consisted of anilofos

application, provided the herbicide and N application method do not cause excessive N losses.) Applying herbicide with the knapsack sprayer or sprinkler bottle resulted in higher weed DM, but significantly less than with hand weeding.

Grain yields were similar for all herbicide carrier treatments but were significantly lower with hand weeding.

Effect of herbicide mixtures in transplanted rice

G. Srinivasan and P. Pothiraj, Agronomy Department, Tamil Nadu Agricultural University, Coimbatore, India

We evaluated the efficiency of some new herbicide mixtures in transplanted rice

Effect of time and method of application of herbicides on weed growth and yield of rainfed lowland rice.

Treatment a

Butachlor 12.6 (160) 273 111 1 DAS

Butachlor 38.2 (1460) 200 86 7 DAS Butachlor 43.9 (1930) 205 51 7 DAS with sand Thiobencarb 31.4 (990) 189 62 1 DAS Thiobencarb 7 DAS Thiobencarb 30.6 (933) 235 100 7 DAS with sand 2,4-D EE 40.8 (1660) 187 102 2.6 1 DAS 2,4-D EE 22.7 (513) 262 105 3.1 7 DAS Pendimethalin 1 DAS Hand weeding 2.4 (5) 277 112 20 and 40 DAS Unweeded control 52.2 (2833) 5 23 0.1

LSD (0.05) (16.5) 72 13 2.9

Weed dry weight

valuesb (no.) (t/ha)

29.8 (890) 241 101 2.8

19.2 (367) 265 106 3.2

log transformed Panicles/m 2

(no.)

Filled Grain grains/panicle yield

3.3

2.5

1.7

1.9

2.7

3.5

aDAS = days after sowing. bValues in parentheses are weed wt in kg/ha.

T. Y. Reddy and K. Bharghavi, Agronomy Department, S.V. Agricultural College, Tirupati, India

Effect of time and method of application of herbicides on yield and yield components of rainfed lowland rice

Effect of weed control treatments on weed population, weed dry matter, and grain yield of rice.a Coimbatore, India.

Rate Weed population (no./m 2 ) at 40 DT Total weed Grain Cost of Treatment b Timingc

(kg ai/ha) Grass Sedge Dicot Total dry matter yield weed control

(g/m 2 ) (t/ha) ($)

EPTC + 2,4-D PE 1.12+0.56 9.0 b 10.7 d 10.3 c 30.0 c 14.1 c 5.8 a 19.25 Molinate + 2,4-D PE 1.80+0.56 3.7 a 2.0 a 3.8 a 9.5 a 10.1 ab 6.2 a 35.85

EPE EPTC - propanil 1.44-1.44 20.2 c 13.5 e 11.3 c 45.0 d 19.9 d 5.5 a 27.64 Molinate - propanil EPE 1.44-1.44 8.7 b 7.8 c 11.5 c 28.0 c 12.2 bc 5.9 a 40.00 Butachlor PE 1.50 6.2 ab 7.5 c 6.3 b 20.0 b 13.8 c 5.8 a 20.73 Hand weeding twice – 4.0 a 5.2 b 4.0 a 13.2 a 9.3 a 6.2 a 40.65 Unweeded check – 104.5 d 31.5 f 38.0 d 174.0 e 73.5 e 3.1 b -

a Means of four replications. In a column, means followed by the same letter are not significantly different from each other by DMRT. b + = tank mixture, – = proprietary mixture. c PE = preemergence, EPE = early postemergence.

in a field experiment at the university farm summer 1986. Treatments were EPTC + 2,4-D (ethyl ester), molinate + 2,4-D, and EPTC - propanil and molinate - propanil compared with butachlor, hand weeding twice (HWT), and an unweeded check. The herbicides were applied as preemergence (3 d after transplanting [DT]) or as early postemergence (12 DT).

Major weed flora in the experimental field were Echinochloa crus-galli, Echinochloa colona, Cyperus difformis, Eclipta prostrata, Ammannia baccifera, and Monochoria vaginalis. Preemergence application of molinate + 2,4-D effectively controlled all three groups of weeds (see table).

At 40 DT, grass weed control by

molinate + 2,4-D was comparable with that by butachlor; control of sedge and broadleaf weeds was superior to all other herbicides. Molinate - propanil and EPTC + 2,4-D also were promising. HWT was comparable with molinate + 2,4-D. Costs of weed control were highest for hand weeding twice and molinate - propanil.

We studied the effect of time and method of herbicide application on yield and yield components of rainfed lowland rice during wet season 1987. Four herbicides were applied with sand or water at different rates and times. Butachlor, thiobencarb, and pendimethalin were applied at 1.5 kg ai/ ha, 2,4-D at 0.9 kg ai/ ha, in 1 ,000 liter water/ ha or in 60 kg sand/ ha.

BPT2740 was drill seeded on unpuddled soil 17 Aug 1987. Fertilizer was 100 kg N as urea, 17 kg P as single superphosphate, and 50 kg K as muriate of potash/ ha. The crop was grown under rainfed condition to 40 d after seeding (DAS), then irrigated. Weed dry weight was measured 60 DAS.

equivalent to hand weeding (see table). Pendimethalin at 1 DAS or 2,4-D at 7

Butachlor applied 1 DAS was DAS was similar to butachlor applied 1 DAS.

IRRN 14:4 (August 1989) 39

Farm machinery

Effect of soil moisture content on power requirements

T. M. Lando, Agricultural Engineering Department, Maros Research Institute for Food Crops, P.O. Box 173, Ujung Pandang, South Sulawesi, Indonesia

We measured power requirements at different soil moisture levels, with soil moisture as the main factor and plowing depth as the subfactor in a split-plot design with four replications.

Soil was red yellow Podzolic with clayey texture. The area at Pulung Kencana Village, North Lampung District, Lampung Province, was flat and covered by cogon grass Imperata cylindrica . The cogon grass was cut and burned before the experiment started.

Treatments were 10, 15, 20, and 30% (wet basis) soil moisture and 10, 15, and 20 cm plowing depth. Plowing width was 20 cm and tractor speed was 5.4 km/h (1.5 m/s) using a 4-wheel 45-hp tractor IH354 and a 9-hp Kubota hand tractor.

Soil draft resistance was measured by fixing a drawbar dynamometer between the 4-wheel tractor and the hand tractor. Drawing power required was calculated as

Pwr = resistance (kgf)×speed (m/s)

75

Table 1. Average soil draft resistance at 5 soil moisture levels and 3 plowing depths. North Lampung, Indonesia.

Plowing Average soil draft resistance a (kgf) depth (cm) 10% 15% 20% 25% 30%

10 815.0 b 787.5 b 750.0 a 922.5 c 1175.0 h 15 920.0 c 907.5 c 825.0 b 1137.5 g 1290.0 j 20 1040.0 f 922.5 e 967.5 d 1225.0 i 1400.0 k

CV Soil moisture (%) 2.3 Plowing depth (cm) 1.7

a Means with the same letter do not differ significantly at 5% level by DMRT.

Table 2. Power requirements at various levels of Draft resistance differed significantly soil moisture and plowing depth. North Lam- pung, Indonesia. with soil moisture levels and plowing

depths (Table 1). Highest resistance was Soil Plowing Power requirement at 30% soil moisture and 20 cm plowing

moisture depth (%) (cm) hp kW depth.

10 10 16.3 15

12.2 resistance was higher at 25 and 30% soil 18.4

20 20.8 13.7 moisture levels. At 10% soil moisture, 15.5

15 15.8 11.7 the hard, cohesive soil was difficult to 15 18.2 13.5 cut and invert. At 15 and 20% moisture 20 19.9

20 10 15.0 11.2 levels, soil was easy to till and resistance 15 16.5 12.3 was relatively low. 20 19.4 14.5

25 Plowing depth also contributed to

10 18.5 15 22.8 17.0 high draft resistance: the deeper the cut, 20 24.5 18.3 the higher the resistance, primarily

30 10 23.5 15

17.5 because of the large volume of soil cut 25.8

20 28.0 20.0 19.2 and inverted.

For all plowing depths, draft

Soil draft resistance is linearly proportionate to power requirements: the higher the resistance, the more

Where, Pwr = required drawing power needed to draw the plow at the same speed (Table 2).

resistance = total soil draft resistance, and speed = speed of tractor.

power (hp),

Postharvest technology replications. One lot was stored at original moisture content (IR8—23.1, 19.6, 19%; PR108—22.3, 18.8, 18%;

Uric acid content of stored rice

and Technology Department, PAU, Basmati 370—19.2, 17.5, 19%) and one Ludhiana 141004, India lot was dried to 12% moisture with a

forced air circulation dryer and stored. Uric acid, the main constituent of insect Both lots were stored in gunny bags excreta, is taken as an index of insect under ambient conditions for 1, 6, and infestation. We studied IR8, PR108, and 12 mo. Basmati 370, representing coarse, Harvest time was not significantly

Y. S. Dhaliwal, Food Science and Technology Department, Punjab Agricultural University (PAU), Ludhiana 141004 (present address: Home Science Department, Himachal Pradesh Krishi medium, and fine varieties, harvested at correlated with uric acid content of Vishva Vidyalaya, Palampur 176062); K. S. three different times (7 d early, milled rice (see table). Uric acid content Sekhon and H. P. S. Nagi, Food Science recommended maturity, 7 d late) with 3 significantly increased with duration of

40 IRRN 14:4 (August 1989)

13.8

14.8

10

Effect of harvest time, drying, and length of storage on uric acid content of milled rice. Ludhiana, India.

Uric acid content (mg/100 g)

Without drying With drying Harvest

Variety time

1 mo 6 mo 12 mo Mean 1 mo 6 mo 12 mo Mean

IR8 Early 4.13 8.64 10.50 Normal 4.13 8.63 9.75 Late 3.75 8.62 9.00 Mean 4.00 8.63 9.75

PR108 Early 5.25 7.88 9.38 Normal 4.50 7.50 9.00 Late 4.50 6.75 10.13 Mean 4.75 7.38 9.50

Basmati Early 3.75 4.50 7.13 370 Normal 4.88 6.75 7.13

Late 4.50 6.00 6.38 Mean 4.38 5.75 6.88

LSD (0.05) Harvest time = ns. Drying = 0.30. Storage time = 0.36. Varieties = 0.36.

7.76 3.75 9.00 9.00 7.25 7.50 3.38 9.00 9.00 7.13 7.12 3.75 8.25 8.63 6.88 7.46 3.63 8.75 8.88 7.09

7.50 3.76 6.00 9.38 6.38 7.00 3.75 6.38 7.50 5.88 7.13 3.74 6.75 7.50 6.00 7.21 3.75 6.38 8.13 6.09

5.13 3.75 6.00 6.75 5.50 6.25 3.75 6.00 7.13 5.63 5.63 3.38 5.63 6.00 5.00 5.67 3.63 5.88 6.63 5.38

storage and was higher in samples stored without drying.

PR108 and Basmati 370.

were Corcyra cephalonica, Sitophilus oryzae, and Sitotroga cerealella.

IR8 had higher uric acid content than

The predominant insect species found

The International Azolla Newsletter is published for researchers in the development and application of azolla in rice production. Its content focuses on discussions of current issues; it does not publish research reports. For more information, write Dr. I. Watanabe, Azolla Newsletter editor, IRRI, P.O. Box 933, Manila, Philippines.

Farming systems Effect of rice planting method, irrigation, and The cumulative effect of tillage and tillage in wheat after rice on yields of rice, irrigation in wheat also did not wheat, and jute in West Bengal, India, 1983-85. significantly affect rice yield.

Establishing wheat with minimal tillage and irrigation after rice

B. Mazumdar, N. R. Das, and B. N. Chatterjee, Agronomy Department, Faculty of Agriculture, Bidhan Chandra Krishi Viswavidyalaya, Kalyani 741235, Nadia, West Bengal, India

We grew rice - wheat - jute in a 2-yr field experiment 1983-85 in a low-lying field. IR579 rice (120 d duration) was grown in both wet seasons, direct seeded and transplanted, with 100-50-50 kg NPK/ ha. UP-262 wheat (120 d duration) was grown with 100-50-50 kg NPK/ ha immediately after rice (mid- Nov) with two levels of irrigation and four levels of tillage. Rupali jute (90 d duration for fiber) was sown in mid-Apr with 50-25-25 kg NPK/ ha and fiber was measured the third wk of Jun for direct seeded rice and Jul for transplanted rice.

The experiment was laid out in a split-split-plot design, with rice in the main plot, irrigated wheat in the subplot, and wheat tillage after rice in the sub-subplot, with four replications. The soil of the experimental site (22.39° N, 88.54° E) was alluvial, with 0.55%

Yield (t/ha)

Rice a Wheat Jute Total Treatment

Rice planting method Broadcast 1.8 2.8 0.7 5.3 Transplanted 2.4 2.2 0.8 5.4

LSD (0.05) ns ns ns Tillage b for wheat after rice

No tillage 2.9 2.0 0.7 5.6 Minimum 2.9 2.6 0.8 6.3

Normal tillage 3.0 2.8 0.7 6.5 Irrigation + 2.9 2.4 0.7 6.1

tillage

normal tillage LSD (0.05) ns ns ns

Irrigation in wheat

initiation + flowering

initiation, late tillering, flowering, milk stage LSD (0.05) ns ns ns –

rows opened with hand-drawn tine. Minimum a Av of 2 yr. b No tillage = soil between rice

tillage = 2 plowings with bullock, lengthwise and crosswise, followed by laddering. Normal

and crosswise, followed by laddering. tillage = 4 plowings with bullock, lengthwise

At crown root 3.1 2.4 0.8 6.3

At crown root 2.8 2.5 0.7 6.0

organic C, 16 kg P/ha, 21 kg K/ha, and pH 6.9.

Broadcast and transplanted rice yields did not significantly differ (see table).

-

Wheat grain yields after rice, rice planting method, tillage operation, and irrigation did not differ significantly.

significantly with tillage and irrigation in preceding wheat.

In total production, transplanted rice was better than direct seeded. Four plowings and two plowings were equally good for wheat, but two irrigations were better than four irrigations.

Jute fiber yield did not differ

A rice-based intercropping sequence for Vindhyan red loam soils of eastern Uttar Pradesh

S. N. Prasad, J. P. Singh, K. Singh, and M. Singh, Agronomy Department, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India

Potential annual yield of crops on well- drained Vindhyan red soils (based on water availability and soil waterholding capacity) is estimated at 2-4 t/ha. But actual production is only 0.5-1 t/ha. The wet season is the main cropping season and upland rice occupies most of the area.

IRRN 14:4 (August 1989) 41

Table 1. Grain and rice equivalent yields as sole crop and intercrop. Varanasi, India, 1985-86.

Yield (t/ha)

Treatment Rice Net return

Rice Intercrop equivalent (US$)

1985 1986 1985 1986 1985 1986 1985 1986

Sole rice in 30-cm rows Sole rice in paired rows (20+40 cm) Sole pigeonpea in 60-cm rows Sole black gram in 30-cm rows Sole sesame in 30-cm rows Rice + pigeonpea (1:l) in 30-cm rows Rice + black gram (1:l) in 30-cm rows Rice + sesame (1:l) in 30-cm rows Paired rows rice + pigeonpea (2:l) Paired rows rice + black gram (2:l) Paired rows rice + sesame (2:1)

LSD (0.05)

2.20 1.60 – – 2.20 1.60 2.20 1.50 – – 2.20 1.50

– – 0.77 0.69 1.70 1.60 – – 0.91 0.75 1.80 1.50 – – 0.56 0.47 1.70 1.50

1.00 0.70 0.44 0.38 2.01 1.57 1.30 0.87 0.55 0.43 2.40 1.73 0.74 0.53 0.36 0.26 1.88 1.33 1.66 1.04 0.24 0.19 2.22 1.50 2.10 1.48 0.41 0.38 2.92 2.24 0.92 0.63 0.32 0.23 1.93 1.37 0.095 0.065 – – 0.127 0.095

153.45 63.15 149.92 57.35 128.60 104.41 135.00 87.94 141.69 99.26 123.89 58.89 201.32 103.45 136.17 57.64 112.27 8.75 228.75 132.42

97.86 10.29 14.85 13.30

The red loam soils offer the possibility randomized block design. of companion pulses or oil seed crops, Rice grain yield differed significantly to stabilize and increase production. We with intercropping pattern in both years tested an intercrop combination during (Table 1). Rice alone in rows 30 cm 1985-86. apart produced maximum grain yield of

The soil of the experimental field had 2.2 t/ ha the first year and 1.6 t/ ha the 0.3% organic C, 0.035% total N, 64 kg second year. Rice + sesame gave the available P, and 201 kg available K. lowest rice yield. Rice + black gram Crop varieties used were Akashi for rice, (2: 1) gave the same rice yield as rice T21 pigeonpea, T9 black gram, and T13 alone, in both 30 cm rows and paired sesame. The experiment was laid out in rows.

Table 2. Land equivalent ratio (LER) of inter- cropping. Varanasi, India, 1985-86.

LEK a

1985 1986

Rice + pigeonpea (1:1) in 1.05 1.01

Rice +black gram (1:1) in 1.21 1.14

Rice + sesame (1:1) in 30 0.99 0.88

Paired rows of rice + 1.09 0.96

Paired rows of rice + black 1.41 1.46

Paired rows of rice + 0.99 0.90

Treatment

30-cm rows

30-cm rows

cm rows

pigeonpea (2:1)

gram (2:1)

sesame (2:1)

LSD (0.05) 0.06 0.07

a fraction of its monoculture check. a LER = sum of the yields of each intercrop a)

Rice + black gram 2:l had the highest net return ($229 and $132/ha). Highest land equivalent ratio (LER) was also with rice + black gram 2: 1, followed by rice + black gram 1:l; the lowest LER was with rice + sesame (Table 2). Rice exhibited the highest competitive ability with pigeonpea and the lowest with sesame.

Effect of green manure and inorganic N in rice - rice - pulse cropping system

P. Balasubramaniyan, SP. Palaniappan, and H. J. Francis, Centre for Soil and Crop Management, Tamil Nadu Agricultural University, Coimbatore 3, India

We studied the effect of green manure and inorganic N on total yield of a rice - rice - pulse cropping system in the field 1987-88. The study was laid out with green manure in the main plot and inorganic N in the subplots, in a split- plot design with three replications.

8.3, CEC 26 meq/ 100 g soil, and 248-24- green manure treatment are not significantly different by Duncan’s Multiple Range Test. 780 kg available NPK/ ha.

field was cut 45 d after sowing, chopped applied at 0, 100, 150, and 200 kg/ ha in basal at 22 kg/ ha. Green gram Co 3 was and buried at 12.5 t/ha, 1 wk before four equal splits: basal, at tillering, raised without manure after wet season transplanting rice (IR50 in the dry panicle initiation, and heading. K was rice. season, IR60 in the wet season). N was split-applied with N at 42 kg/ha. P was Green manure significantly increased

Soi1 was clay loam (Alfisol) with pH Effect of organic and inorganic N on rice - rice pulse yields. Treatments identified with the same letter within a

Crotalaria juncea raised in a separate

42 IRRN 14:4 (August 1989)

rice yields in both seasons: + 1.0 t/ha in the dry season, + 0.5 t/ha in the wet season (see figure). Rice yields increased with increased N. Highest yield in the

Residual effect of fertilizer applied to rice in rice - fallow - cotton

S. Natanasabapathy, T. Lakshminarayanan, and K. M. Ramanathan, Tamil Nadu Rice Research Institute, Aduthurai, India

In Cauvery delta of south India, rice - rice - cotton and rice - cotton are common crop rotations. We evaluated the effect of fertilizer applied to the second season rice crop on rice - fallow - cotton during 1987 and 1988.

Experiment field soil was Entic Chromustert with pH 7.4, CEC 30.8 meq/100 g, 0.75% organic C, 295-15-325 kg available NPK/ha and E.C. 0.2 dS/m.

The experiment was laid out in a split-plot design. Main plot treatments were rice with no fertilizer and 100 kg N, 22 kg P, and 42 kg K/ha individually and in combination. The subplots were

Effect of source and level of nitrogen on yield of rice and succeeding lentil crop

G. Singh, O. P. Singh, R. S. Singh, and R. A. Yadava, N. D. University of Agriculture and Technology, Crop Research Station, Ghagharaghat, Bahraich 271901, Uttar Pradesh, India

We studied the residual effect of urea and modified urea on yields of rice and a succeeding lentil crop grown without fertilizer 1986-87 and 1987-88.

The soil was sandy to clay loam with pH 8.1; 0.38% organic C, 10 kg available P/ha, 233 kg available K/ha. Wet season rice was followed by dry season lentil in a randomized block design with four replications.

N source had a significant residual effect on the succeeding lentil yield (see table). Urea supergranule (USG) deep placement in rice had the highest

dry season was with 200 kg N/ha; and significantly with residual green manure with 100 kg N/ha in the wet season. or applied N at rates above 100 kg Green gram yields did not vary N/ha.

Residual effect of fertilizer applied to rice on cotton yields in a rice - fallow - cotton rotation. Adu- thurai, India, 1987-88.

Yield (t/ha) Fertilizer to rice

(kg NPK/ha) Fertilizers applied to cotton

First year Second year Mean

0-0-0 60-13-25 30-6.5-12.5 Mean 0-0-0 60-13-25 306.5-12.5

0-0-0 1.0 1.4 1.4 100-0-0 1.3 1.5 1.4 100-22-0 1.5 1.6 1.5 100-0-42 1.5 1.6 1.6 100-22-42 1.6 1.7 1.7

Mean 1.4 1.6 1.5 LSD between 2 fertilizer treatments of rice at

LSD between 2 fertilizer treatments of cotton different levels of fertilizer to cotton

at different levels of fertilizer to rice

1.3 1.4 1.7 1.4 1.6 1.9 1.5 1.5 1.9 1.6 1.9 1.9 1.6 1.5 2.1

1.6 1.9

0.7

1.0

1.5 1.5 1.9 1.8 1.8 1.7 2.0 2.0 1.7 1.8 1.8

1.7

2.4

rice - fallow - cotton (MCU7) with no effect of 100-0-42 kg NPK/ha applied to fertilizer, 60-13-25 kg NPK/ha and 30- the preceding rice crop was pronounced 6.5-12.5 kg NPK/ha. (see table). The residual effect of P on

cotton was adequate, since the residual Half the fertilizer recommended for cotton was negligible.

Effect of source and level of N on grain yield of rice and the residual effect on lentil yield. Crop Research Station, Ghagharaghat, India, 1986-87 and 1987-88.

Treatment Rice yield (t/ha) Lentil yield (t/ha)

1986 1987 1986 1987

Nitrogen sources Prilled urea (1/2 basal + 1/2 topdressed

Prilled urea (1/2 basal + 1/2 foliar spray

Lac-coated urea (basal) Neem-coated urea (basal) Urea supergranules (placed 8-10 cm deep

after first flood receded)

after first flood receded)

after first flood receded)

LSD (0.05) Nitrogen level (kg/ha)

0 30 60

LSD (0.05)

2.0

2.0

2.7 2.8 2.9

0.2

1.1 2.7 2.9

0.2

1.7

1.6

2.4 2.6 2.8

0.2

1.1 2.5 2.7 0.2

1.2

1.2

1.3 1.4 1.7

0.2

0.9 1.3 1.5

0.1

1.1

1 .0

1.2 1.3 1.6

0.2

0.8 1.2 1.4 0.1

residual effect on lentil yield; neem- modified urea applied to rice is coated urea (basal) and USG did not explained by the significantly lower loss differ statistically. Prilled urea in 2 splits of N through leaching, denitrification, had very low residual effect. and ammoniacal volatilization.

The increase in lentil yield after

IRRN 14:4 (August 1989) 43

Residual effect of urea forms on winter rice. Aduthurai, India, 1986-88.

Summer rice grain Available soil N yield (t/ha)

Treatment 1986-87 1987-88 1986-87 1987-88 1986-87 1987-88

N level (kg/ha) 0 4.3 4.3 229.8 239.5 3.1

37.5 75.0

112.5 150.0

LSD (0.05) 0.2 0.2 ns ns ns ns Forms of urea Prilled urea 5.9 6.3 258.0 252.3 2.9 4.1 Urea supergranule 6.0 6.4 241.3 243.2 3.1 4.0 Sulfur-coated urea 6.0 – 258.5 253.2 3.2 Neem cake-coated urea 6.8 6.4 249.3 251.4 2.9 Gypsum-coated urea 5.8 6.2 251.5 247.1 3.0 3.6 Rock phosphate urea 5.7 6.1 250.5 252.0 3.1 3.8 Plastic-coated urea – 6.3 – 250.2 – 3.8

LSD (0.05) 0.2 0.1 ns ns ns ns

5.3 5.6 252.0 248.1 3.1 4.1 6.2 6.1 249.8 247.8 6.7 6.7 264.0 258.8 6.7

(kg/ha) (t/ha)

6.7 262.0 254.1 3.2 3.6

Winter rice grain yield

3.7

2.6 3.0

3.7 4.1

– 3.9

Residual effect on succeeding winter rice of urea applied to summer rice

S. Ramasamy and R. Rajendran, Agronomy Department, Tamil Nadu Agricultural University, Coimbatore 641003; and P. Selvaraj, TRRI, Aduthurai 612101, India

We studied the residual effect of different slow-release urea forms applied to Jun-Oct rice (ADT36) on the succeeding Oct-Feb rice (IR20) in 1986-88.

The soil was a clay loam with 254- 13.4-113.7 kg NPK/ ha. The N materials used for the short-duration summer rice were urea supergranule, sulfur-coated urea, neem cake urea, gypsum-coated urea, rock phosphate-coated urea, and prilled urea (PU) at 0, 37.5, 75.0, 112.5, and 150.0 kg N/ha. Half of the recommended N (50 kg/ ha) as PU was applied to the succeeding winter rice in three splits: 50+11+21.

Soil analysis after harvest of summer

rice showed no significant difference in We infer that slow-release urea available soil N due to form or level of materials did not leave any residue in urea. Winter rice as a residual crop did the field after 110 d (period between not show any yield response to urea urea basal application and postharvest form or N level (see table). soil sampling).

SOCIOECONOMIC AND ENVIRONMENTAL IMPACT Livelihood

Energy use in rice - wheat cropping system

B. P. Singh, Indian Lac Research Institute, Bamkum, Ranchi 834010; and D. C. Ghosh, Institute of Agriculture, Visva-Bharati, Sriniketan 731236, West Bengal, India

We estimated the energy used in various cultural operations for a rice - wheat sequence with recommended and low input levels at Birsa Agricultural University Farm, Kanke, Ranchi, 1984-86.

At the recommended inputs, rice variety Sita was transplanted the second week of Jul at 15- × 10-cm spacing; wheat cultivar Sonalika was sown the

44 IRRN 14:4 (August 1989)

third week of Nov (22 rows). Both crops received 100-2-25 kg NPK/ ha and adequate plant protection.

At low inputs, rice and wheat were sown 15 d later with 25% lower plant density, 50% less fertilizer, and only seed treatment plus one hand weeding.

Rice received one irrigation at flowering and 106 cm monsoon rain during vegetative growth. Wheat received four irrigations and only 4.7 cm rainfall.

Data on direct and indirect sources of energy were obtained from the equivalent energy values of inputs and outputs (Table 1). Energy output through grain yield together with energy use efficiency (output/input ratio) and energy productivity were estimated.

and wheat at recommended and low input levels are presented in Table 2.

Energy input and output data for rice

Table 1. Equivalent direct and indirect sources of energy. West Bengal, India.

Energy source

Input Human labor - adult man h 1.96

adult woman h 1.57 Bullocks (medium) Pair/h 10.10 Diesel fuel Liter 56.31 Fertilizer N kg 60.60

Unit Equivalent energy (MJ)

P kg 24.98 K kg 8.04

Seed - Rice kg 14.80 Wheat kg 14.40

Pesticide - Aldrin 5% dust kg 10.00 BHC 5% dust kg 10.00 Butachlor kg 10.00

Dimethoate kg 120.00

Agrosan GN kg 120.00 Isoproturon kg 120.00

Irrigation cm/ha 46.02 Output

Rice kg 14.80 Wheat kg 14.40

(Punch-G)

35 EC

(Taurus-50)

Alley Farming Network for Tropical Africa

The Alley Farming Network for Tropical Africa (AFNETA) commenced operations 1 Feb 1989. Its objectives are to promote alley farming research and on-farm testing in different environments.

AFNETA is cosponsored by IITA, ILCA, and ICRAF. Collaborators are scientists in national agricultural research systems.

ERRATUM Using silica gel desiccant to dry rough rice samples, by P. A. Clarke and M. A. Quasem. 14(2) (Apr 89), p. 14.

The regression equation in paragraph 3 should read:

Y= 4.17 X 0.38 ; r=0.91, p=0.01.

Correspondence can be addressed to the network, c/o IITA, Oyo Road, PMB 5320, Ibadan, Nigeria (Cable:

New IRRI publications

Hybrid rice Weeds reported in rice in South and

Southeast Asia, by K.M. Moody A guide to creating self-learning

materials, by D.R. Minnick World rice statistics 1987

TROPFOUND IKEJA; telex: TDS IBA NG 20311 [Box 0151 or TROPIB NG 31417).

IPM Newsletter discontinued

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Chemical fertilizer is the major energy input. Seed, sowing/ transplanting, and land preparation are the next most important energy inputs.

Total energy input and total energy output were higher with recommended inputs, energy use efficiency was greatest with low inputs. Energy productivity was not affected by low inputs.

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Table 2. Energy inputs and outputs in rice - wheat production. a West Bengal, India.

Inputs and outputs (MJ/ha)

Energy use Rice Wheat

Recommended Low Recommended Low inputs inputs inputs inputs

Land preparation 1,689.9 1,689.9 (16.6)

Seed and sowing or 2,338.3 1,840.4 2,127.0 1,767.0

1,546.8 (13.5) (20.7) (11.4)

1,546.8

transplanting (18.8) (22.6) (15.7) (19.0) Fertilizer and application 6,870.9 3,433.4 6,903.8 3,451.9

(55.1) (42.1) (50.9) (37.1)

Plant protection 616.9 302.0 467.4 192.1 (4.9) (3.7) (3.4) (2.1)

Irrigation 349.6 349.6 1,398.6 1,398.6 (2.8) (4.3) (10.3) (15.0)

Harvesting and threshing 591.9 536.2 1,120.2 942.0 (4.8) (6.6) (8.2) (10.1)

Total energy input 12,457.5 8,151.5 13,563.8 9,298.4 Total energy output 62,569.9 56,682.6 47,809.7 4,0610.5

Energy output:input ratio 5.02 6.95 3.52 4.37 Energy productivity (g/MJ) 390.1

a Figures in parentheses indicate percentage of total energy input.

407.9 260.4 256.2

ANNOUNCEMENTS

IRRN 14:4 (August 1989) 45